my girl friend an i just split up,she is on my contract.

you can call customer care and get it canceled and they will let you know if there is a cancelation fee (chances are yes if you got the phones within the last 2 years). there is an option to get rid of the account with out the fee and thats a transfer of liability where you put the phone in her name and she is liable for the service and charges. both parties have to agree for this so you will have to get her to go to a sprint store with you to do this. if thats not possible then the cancelation is your other option