shops WONT fix it?? i hav a nextel cell phone and the screen isnt working, about 1 year agoe i had gotton a faceplate for it and then just a couple months later my Flip/screen broke and i got it replaced with a differnt flip and screen...now the flip and screen isnt working again so i went to a differnt repair shop and they said that since i got the faceplate that my phone doesnt hav warrenty or somthing,,,how come the OTHER place could fix it and now this place is saying theyre not allowd to??? i dont get this? can someone explain

Because Nextel Customer Service is completely ridiculous. I would get out while you still can. They do not care about Customer Satisfaction, not even a little bit.
All service providers have a deal where the warranty does not apply if you put accessories like that on your phone because that is not how they sold it to you. You got lucky that the first person fixed it. All I can say is get out of Nextel's hold while you still can ... they are RIDICULOUS!!!!!!!!!!!!!!!!!!!!!!