1. contact live support
2. make up some story about your girlfriend / friend being in russia and that he/she thought it would be a nice idead to buy you the game, after installing registering ... yadda yadda... you noticed that its russian and you dont understand jack in that language...
3. ???
4. profit
(if the support guy asks you if its digital or retail say its digital)
took me like 5hrs constantly contacting support, got rejected like 30+ times but then finally somone gave in. had even reports of ppl getting it like the 2-4th time they contacted and also getting 15% off coupon for next purchase ^^