Be aware that, unless the policy is changed, when you purchase online you have to ship the phone back when you return it. I don't think you will get your upgrade credit back until their shipping departments records receipt of the phone. Make sure you save any paperwork and record your tracking number. When the shipper reports phone as delivered, print off a copy showing that. I don't think you will get the next phone until it is recorded that you returned the first one. If you are uncertain about keeping the phone I would encourage you to purchase it at a corporate T-Mobile store, not third party.