Maybe you can chat in Bittrex's trollbox about this? It seems that the user who own the address is also trading there. I saw on Etherscan that his OUTGOING transactions were sent to Bittrex, see this as reference:
https://etherscan.io/address/0x813e73b19889d30bb221742cafa6ec7c92175d59#tokentxnsI don't know if Bittrex Admins can help you locate the owner, but try to contact them as well. I hope the owner of the address will send it back to you if ever you talk. Good luck and be careful next time so that you won't be a victim again.
I just contact bittrex admin forasking can i get some information about the address owner but no any respon, if i get ex email, i want talk to him for win-win solution to get my coin back, because im very-very need that coin for costs my college.
i'm not sure if trex will provide this information to you mate, but hopefully you will able to trace the owner of that address so you can try talk and give your offer, its next to impossible but keep trying and hope for the best mate. good luck