Please delete Dominion and Shuffle IT account under this same username, thanks.
(There should really be an in-game deletion. Someone could use this Support forum maliciously.)
Done!
Abuse is prevented by comparing email addresses from the games account with those of the forum account, which match for you (otherwise I ask in a PM about the game account email adress).
In a small operation like this, where the amount of requests is still handable, it's hard to convince the (sometimes only) person working on the code that the most important feature right now is account deletion.