The project manager should first follow up on the payment request with the payable clerk because this is the most direct and appropriate first action to understand the payment status. In a functional organizational structure, authority over finance, procurement, and accounts payable usually belongs to functional departments rather than the project manager. The project manager should coordinate and remove obstacles, but should not bypass normal financial controls or authorize payment from contingency funds without proper authority. Negotiating with the contractor may be necessary later, but only after confirming whether the payment is pending, blocked, missing documentation, or delayed by process. Escalating to the financial controller is appropriate if routine follow-up does not resolve the issue or if the delay creates serious project impact.