I recently switched to Verizon and purchased Lumia 735s for my family, but have had so many billing problems in the 5 weeks I've been with Verizon that I'm thinking of going back to AT&T. Would I be able to use the phones I currently have or would I have to use something else? If I have to, I'd just pick my parents up a couple of 640 Go Phones as replacements. Any help would be appreciated.