Apple does not approve or decline transactions. In fact Apple does not participate in the transaction process. When a user initiates an Apple Pay transaction by double clicking the side button and Face ID verifies the user, tapping the transaction terminal sends encrypted payment information to the merchant. The merchant records a transaction number and their POS system sends encrypted data to the payment process. The encrypted data goes to the Payment Network Operator (Visa, MasterCard, American Express etc.) and if they approve, it’s sent to your bank for final approval. Your bank verifies the details of the transaction and approves or declines the transaction. Apple does not participate at any point in the transaction. Any information about the transaction that appears in your Wallet was provided by you bank.
If the charges aren’t yours you need to be talking to the fraud department at your bank, not the customer service team. Having worked in the financial industry, my experience is that the first tier customer support at most banks have no clue how Apple Pay works. The bank’s fraud department is much better trained in these matters and will be able to assist with a refund. Good luck.