Did you ever get a screenshot or note of your Mayhem ID ??
If not you may be able to get Help to transfer your account to a new useable email, but you'll need to go through a lot of security checks with them.
One big tip on that, make sure the answer is whatever you put on your account.
If asked about purchases only mention other EA games on your account that needed license keys, not buying or using Donuts etc. If that's none then the answer is no purchases.
If it doesn't match the info on your account completely they'll not accept it is your game.
For info on the Mayhem ID and getting Help Click Here