I actually don't think the ESC was at fault - I suspect either the motor is shot or poor connections with the motor... Cogging is the indication that something in the setup is wrong...
My German's not what it was but isn't it more like 15 eur...
http://www.dhl.de/de/paket/privatkun...paeckchen.html
The reality though is your ESC is now dead and you have no choice but to ship it back... I hope that the vent makes you feel better in some way but there is not a lot that can be done now.
Best of luck.