[mothered]

Well I have just received the empty box from Fedex for the "return", so before I contact them with the disposal of product, is there a easier/quicker way to succed?

The only way Is to box the return, but the Item Is too big, hence signs of tampering will be noticed during the very early stages In transit.

And when you say be prepared for it, you mean to be ready to spend time in chats/replying emails etc.?

Correct.