NLRC Money Claim

Hi I had an employee for only 3 months, who express his resignation but did not wait for 30 days. after 5 days of expressing his resignation verbally, he no longer reported for worked and we received a money claim from NLRC just 7 days after he said he wants to resign. What can we do? because we asked him to wait for 15 days because we need to find a replacement. and we cannot just give him his salary right then and there because, we need to make sure that he did not do something bad because part of his work is getting payment from stores. We have experiences before that employee get the remittance from the store they have collected and never remit it to us. We only discover this once, there is a new employee and that new employee is collecting money from the store in which previous employee has already collected. How can we delay payment of his salary to make sure all is clear and how can we fight this out because it is not our fault that the employee did not wait for 15 days. Our hearing is on aug 2, hope you can help us.