Sounds like maybe they just blew you off (i.e. didn't even search for you tire). On that basis you might try one more call. This time to the service manager. Give him the setup about why you think the tire is there. Then go into the part about no one called you back and that you are concerned that they may not have looked for your tire.

Sure this is a big longshot. But if the service manager says look they may really look. Could be a shop thief might bring the tire back and "find" it at the shop if enough heat is applied. Could also be this type of followup attention will keep a dishonest shop from ripping off a few less people in the future.

Could also be that you can find a rim and tire in Tucson for less than a drive back up to Phoenix to pick yours back up.

Again sorry for the loss.