Holding a resigned employee beyond his notice period - employee is required to collect outstanding payments from the vendor

Hello everyone, My question is regarding holding a resigned employee beyond his notice period for clearing outstanding deliverables at his end. An employee is required to collect outstanding payments from the vendor. He resigns and serves the notice period but does not collect outstanding payments. The manager says that he will be relieved only if he gets the outstanding amount to the organization. Can we hold an employee beyond his notice period?
Regards