Can I still get my iPhone 4s fixed with applecare after i've upgraded?

My iPhone 4s was giving me major issues and I live over an hour away from an apple store with everything going on I just didn't have a chance to schedule an appt and get it fixed. Anyways I had an early upgrade and upgraded to the 5s because my 4s wasn't working and the best buy mobile is right down the street, we have one of those lol. Can I still go get it fixed though? Even though its not hooked up. I would like to use it for an iPod and would like to put it on my plan in a few months once my boyfriends contracts up to avoid another contract. I can't seem to find out and whenever I try calling the apple store I can't get through! I'm actually going to be in the same city as the apple store this weekend so I could potentially get it fixed. I did pay the money for the applecare just like on my iPad, so I feel like I should be able to but anybody who knows for sure please let me know. Thank you!

Added (1). p.s. My applecare is still valid I checked it with the serial number and everything.

You still have it and it's under apple care, I can't think of a reason why they wouldn't do it.