TankiX asking for registration code again

I was invited to play TankiX several months ago. I reserved my Tanki nickname, and played TankiX several times. I deleted the registration code, because I thought I no longer needed it. Now when I try to sign on TankX, it asks me for my registration code again, saying my nickname has already been reserved. Will TankiX headquarters please email me my registration code again? How do I ask them to do that?