Try sending them an e-mail or just mail your ESC to them. I have done this myself and they are good people. They will fix it.
See them here:
http://mgm-compro.com/contacts.php
Losi 8 Buggy + Truggy & Associated SC8
Tekno RC Conversion Kits on all
MMM, MGM, Xcelorin ESC's
Tekno Neu "square can" brushless motors
Polyquest - Neu - Flight Power LiPo's