If a customer acknowledges that they loan their debit card to the daughter who initiated debit card transactions to purchase a train ticket and those transactions were declined on the merchant's end but did post to the customers account, can he come back now and claimed them as unauthorized and present a police report in the name of the daughter to try and get his funds back or just because of the fact that he acknowledge that he gave his card to another member of the family, can we go about declining the transaction

he has previously stated he gave it to her. Unless there are new transactions he hasn't already notified you of, a police report does not change anything.

and if the transaction was declined at the merchant how did it post to customer account?

This has me really confused as well.

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