Wireless Solution Flip Phone Lithium Ion Battery

My sister has been with cellular one for the past 3 and a half years, now that they are Alltell she purchased a new phone several months ago. The battery has now died and the All Tell dealer in San Angelo, Texas tells her that they don't carry the battery for that phone anymore. Even though she can not use her phone anymore they tell her she is still responsible for her service contract. How can the service contract be valid if there is no service. I have gone to the Alltell dealer here in south Texas and they tell me they do not carry that battery either. It seems to me that they either need to give her a new phone or dissolve the service contract. Please send solution to this problem. The battery is an LG battery 800 30539772 3.6x850mad.