Post contract unlocking iPhone 4

I purchased iPhone 4 from Japan during my deputation from my office and was expecting 1 year deputation. but due to some technical reasons my visit was cut short. so i Payed Softbank(japanese carrier) full contract cancellation ammount and completed all legal formalities required. now when i shifted to india and inserted vodafone sim i figured that it's carrier locked.

Now the point is I paid for the device and the penalty for contract cancellation to the carrier, Now what happens to the device? I haven't found any help via internet. can an apple official shed some light on to this case? i am willing to scan and upload all documents if required.

Warm regards

Ashu