have you tried a search on it? I had to get a new 7520 a little while ago because the keys didnt work. If you have to get a new one make SURE that they do a "flip" on it because they will probably give you a old one that used to be a Nextel employees phone.....go figure. if they dont do a "flip" you wont be able to use it.
Apparantly they are notorious for that.