You are screwed. Its a question of law to get the rights to get around the VPN.
look at the AS# on the IP of his you have.
Put the AS# into bgp.he.net, if it's a home provider it's probably a home ip, else it's probably a VPN or server they own.
Sorry for offtopic, I know it wont help you much, but this is one of reasons I do not buy games from Steam, Origin or any other shitty service. GOG FTW, you OWN what you buy.
if he's still using your email you could send him a virus. the virus could not only give you his IP but do serious damage like replacing all his files with pictures of the anuses of donkeys. to symbolize what he is. lol