I think the phone is 2 weeks since bought.

You have 14 days in which to return for refund, after that you will have to talk to the store and see what they recommend doing, often it is sell on eBay or the like and put the money towards a new iPhone 5. Did you get a contract with Sprint? If so you have to find out about the buy-out penalties they will impose on you.

If you take it back to the store they will be able to tell you what the coverage is.