We all know the issues we are having from data connections, sms, mms, rebooting, ect. I'm on my 3rd replacement device and I wish I kept my original one. Not one of the refurbished Thunderbolts, new sim cards, or the 6 master resets I've been told to perform have done anything except clear up an issue for a week or so. In fact the refurbished phones have given me more issues and heart ache then my original purchase. Unless you have tried a master reset and ran your thunderbolt with minimal apps on it for a week or more but still have a problem you can't deal with do not get a refurbished Thunderbolt. I am sick to my stomach that everytime I open the box and start setting up a refurb device and I already feel like it's used garbage. Either the battery cover doesn't fit right, screen isn't lined up properly, or something falls off because it was glued back on or with in a few days it's doing exactly the same **bleep** that the last devices did. My advise is to stick with your original Thunderbolt and keep plugging tech support with your issues.
I have friends that work in the tech support center they both agree that the process to diagnosis your device is always going to be the same.
1. Remove battery
2. Master reset
3. Replace device
Tech support never gets to actually touch or perform tests on the devices they are telling you to do these 3 steps on. They operate off the data base that Verizon provides them. They have only been trained on how to operate the system and deal with customers complaints. When you send in your old device it goes to processing center the person processing it has no idea what was wrong with it they just inspect clear data perform tests maybe install a few new parts at random then box it up and ship it out to the next person complaining about their Thunderbolt and in my experience they haven't fix any of my problems. They'll repeat this process either till you get lucky enough to be satisfied or get 3 replacements in 90 then complain enough that they will replace your thunderbolt with a comparable device.
Good Luck