A call back procedure is a phone-based verification step used to confirm that a supplier has genuinely requested a payment or change to their bank account details.
Callback verification remains an important control against payment fraud. Trustpair supports this process by combining human-led telephone verification by Trustpair agents with automated bank account validation. Depending on the situation, Trustpair can contact the supplier using trusted contact information, verify the payment details verbally, and record the outcome as part of the payment security workflow.
Automation and callbacks are not opposing approaches. Automated validation provides fast, independent checks, while a callback adds direct human confirmation when a telephone conversation is needed. Together, these controls help organisations verify supplier payment information more securely and efficiently.
Key Takeaways:
- A callback is an outbound phone verification used to confirm a supplier’s identity, payment request, or change of bank account details.
- Callbacks should use a phone number obtained from a trusted, independent source.
- Trustpair can perform callback verifications on behalf of its clients through its verification agents.
- Automated bank account validation and callbacks are complementary controls, not mutually exclusive alternatives.
- Combining automation with human-led verification makes payment security more scalable without removing the phone-based checks required for higher-risk situations.
- A strong supplier verification process combines identity checks, account validation, documented procedures, and human confirmation when necessary.
What is a call back procedure?
A callback procedure is a phone-based verification process used to confirm that a payment request or change to a supplier’s bank details is genuine. The organisation makes an outbound call to a trusted phone number and speaks with an authorised supplier contact.
The purpose of a callback is to independently confirm the request, not simply to repeat information received by email. The person conducting the call should ask the supplier to state or confirm the relevant payment details and document the result before payment is released.
Organisations can perform callbacks internally, or they can use a specialist service such as Trustpair to conduct the verification on their behalf. In both cases, the phone conversation remains an important part of the control.
Callbacks are especially useful when:
- A supplier requests a change to payment details.
- A payment request is unexpected or urgent.
- A new supplier is being onboarded.
- The invoice or bank details do not match existing records.
- The request contains unusual information or potential fraud red flags.
- A payment requires additional human confirmation before approval.
For broader guidance, see our article on how to verify bank transfer instructions.
How to perform a secure callback procedure
A secure callback should be part of a documented, multi-layered verification process.
1. Treat unexpected requests with caution
Payment requests and changes to bank details should be reviewed carefully, particularly when they arrive by email or contain urgent instructions. Business email compromise attacks often rely on impersonation, urgency, and social engineering to make fraudulent requests appear legitimate.
2. Use an independently verified phone number
Never rely solely on the phone number included in an email, invoice, or payment request. Instead, use a contact number from an approved supplier database, an existing verified record, or the supplier’s official website.
When a callback is performed by Trustpair, Trustpair agents use trusted contact information as part of the verification process.
3. Apply the four-eyes principle
Where appropriate, the person performing the callback should be different from the person who initiated or approved the payment request. This supports segregation of duties and creates a stronger audit trail.
The four-eyes principle helps ensure that payment decisions are independently reviewed rather than controlled by a single person.
4. Ask the supplier to confirm the payment details
Do not simply ask whether the information shown on an invoice is correct. Ask the supplier to state or confirm the relevant payment details using an independent source.
For additional protection, combine the callback with real-time account ownership verification or instant account verification.
What are the common risks and limitations of manual callbacks?
Manual callbacks remain a useful internal control, but they can be difficult for finance and procurement teams to manage at scale. Common challenges include:
- Limited scalability.
- The time required to make and document calls.
- Unanswered calls and repeated follow-ups.
- Inconsistent application of the procedure.
- The possibility of human error or social engineering.
- Delays to supplier payments and month-end processing.
A callback can reduce the risk of payment fraud, but it does not guarantee that a payment is safe. Employees may not follow the procedure correctly, the contact details may be compromised, or the person answering the call may not be authorised to confirm the request.
For this reason, organisations should use callbacks as part of a broader payment security process that includes independent data validation, segregation of duties, escalation procedures, and a clear audit trail.
How do automation and callbacks work together?
Automation and callbacks serve different but complementary purposes in payment security.
Automated bank account validation can quickly check whether a supplier’s account information is consistent with trusted banking data. This is useful when organisations need a fast, independent verification before making a payment.
A callback provides a direct conversation with the supplier. It can confirm that the supplier initiated a request, clarify unusual or conflicting information, and provide additional reassurance when the risk or circumstances require human verification.
Trustpair combines both approaches. When an automated check is sufficient, it can accelerate the verification process. When a phone conversation is required, Trustpair agents conduct the callback using trusted contact information and document the outcome.
This allows accounts payable and procurement teams to benefit from automation without losing the human verification step.
In other words, Trustpair does not ask organisations to choose between callbacks and automated validation. It helps them apply the right combination of controls to each payment verification situation.
Learn more about how Trustpair protects outgoing payments through payment validation and automated account checks.
Callback procedures and payment fraud prevention
Callback procedures remain an important way to confirm supplier payment requests and changes to bank account details. They provide direct human confirmation, but they can be difficult for internal teams to manage at scale.
Trustpair addresses this challenge by combining automated bank account validation with callback verification performed by Trustpair agents. Automation helps accelerate routine checks, while human-led phone verification remains available when a supplier conversation is needed.
The result is not a choice between callbacks and automation. It is a hybrid payment security process that makes phone verification more consistent, scalable, and traceable while helping organisations prevent payment fraud.
