I had the same issue. Data wasnt working right out of the box. The ONLY solution is to have them replace the phone. trust me. just tell them you've researched the Sprint Support website and that is the solution. Have the store reps get on the phone with support and have them try to fix it because they will not be able to. Ask for a brand new phone.
**Bring your original phone box with all accessories with you to the store because they will need that to do the switch.
You can tell if the phone will have issues right after turning it on for activation. If it asks you to connect to a wifi device then you know Data isnt working.
just wanted to add that after they replaced my phone (literally got the next serial #) my new one works perfectly and is awesome!