I currently have an older Nokia phone with service from an Alaskan carrier (used in Alaska for Business during the summer months) but spend the rest of the year in California (Winter, who wouldn't). I would like to upgrade phones, but the carrier says I have to buy one of theirs ( new contract, expensive, and something about proprietry software). Why can't I buy the same model they sell off the internet (cheaper) and have it programmed to fit the service?