They only provided me with the private Key and asked me to use it somewhere else... is it possible to make the transfer with just the private Key? Or is it over?
It's not over yet, mate

. Transfers can't be made with private key, but private key is your way to access the Dogecoin (DOGE) assets you previously owned. You can browse to find a wallet that supports importing Dogecoin private key, and don't forget @Little Mouse's advice, because you might fall into a scam.