So I guess it's either Squaretrade or my Renters insurance, can I return my Applecare to an AT&T store or do I have to ship it back to them?
you can do it over the phone , you can return AppleCare for a refund, but you won't get your full purchase price back. Instead, you'll get a pro-rated refund based on how long you've had the plan before returning it (in your case you should get full refund if you have not used it at all).
If you decide you want to return your AppleCare plan, call 1-800-APL-CARE and ask to speak to someone about an AppleCare return (you may have to dial the operator for this, as there's no clear option for it in the phone menu).
The person you speak to will ask for your information - including information from your receipt, so have it handy - and then will transfer you to a specialist who will confirm the return. Expect to see your refund check anywhere from a few weeks to a few months later.