So I helped my Uncle buy a 640 XL about 3 months ago and it is now constantly dropping calls and it also beeps and says it I syncing his contacts multiple times a day. I'm thinking he has a radio issue which is causing the dropped calls and maybe failed syncs. I feel bad. I talked him into staying with WP and now this happens. Was going to tell him to go to AT@T and see if they will replace his phone but am thinking he would be better off going to the Microsoft store and dealing with them. Any suggestions on the cause of his issues and where he should go for help? I would hope the MS store would take care of a situation like this but not sure and if he has any more problems he will be another customer they will lose. All help is appreciated.