alltel says se44 will not work... dif versions?

i purchased a brand new slider, se44 from ebay. i was told by alltel that this phone will work with their requirements. cdma ect. to make a long story short i took the phone there and unefon appeared on the screen. she said the phone would not work and she could do nothing for me. is there anyway to get "unefon" whatever off, so that "alltel" whatever can be programed into this phone. by the way... i cant send the phone back!
i did some research on uenfon and it has something to do with a small section in mexico. the user manual was also in spanish.
somebody please tell me this lady is wrong!!!

thanks,
tom