I believe if you purchase from the carrier, you have to take your receipt and activate it yourself. I don't think it is done automatically like it is when you make a purchase directly through Apple. You can use the Contact Support link at the top right of the page here to check with Apple on that.
Apple Care from Sprint
User profile for user: Dvtipton
Question: i purchased my apple care services through my phone company but when i check it on the support page it only shows limited warranty. how long will it take to show on the apple support page?