EAFC Xbox Playtest/ EA Account issues

For the last two playtests I've had access and downloaded but it won't let me access my EA account (I think because it's linked to the same email address, but a different gamertag). Anyone know how I can sort this out as it's driving me crazy!

If I login using the same gamertag as my EA account I can load the game, but not login to the servers for the playtest.

Any ideas?..