FedEx Package Held at Airport, No Clear Instructions for Payment or Customs

I ordered a product from abroad, and it arrived at Sabiha Gökçen Airport but was placed in a warehouse (antrepo). I received an email asking for payment and to send certain documents to my customs representative. However, there’s no clear information on how much I need to pay, why the item was placed in the warehouse, or who I need to contact. It seems I need to make a payment to FedEx for shipping, but I have no idea what steps to take next. This lack of communication and unclear instructions is incredibly frustrating. I need clear guidance on what to do, how much to pay, and who to contact to resolve this issue and receive my package.