Please help. My Iphone5 was texting perfectly to both iphones and non-iphones but now it won't text to other iphones. I can text and receive texts from any phone other than an Iphone. Incoming IPhone texts appear on my IPad and Mac but not on my phone. When I try to send a text to another IPhone, it doesn't appear on my friend's iphone. This problem only occurs when I try to message other IPhones ... it still works with droids, etc. I'm wondering if I inadvertently changed something in my settings. Any suggestions???
You don't say if iMessage was activated. Try a reset on the phone. Hold the sleep/wake and home buttons together until you see the Apple logo and release. This will have no affect on data on the device. See if it works after that. If not, then go to Settings>General>Reset>Reset Network Settings. While this will delete the wifi passwords for existing networks, it does refresh the network. You will have to do into Settings>Messages and activate iMessage again. You will probably need to activate Facetime again as well.
I don't know of an Apple store that charges $20 to fix a phone. If the phone is in warranty and has a defect, they will judge if it should be replaced.