Get out there and get the community service done. Find a church who needs their yard cleaned up for fall, and get a letter for the court once you are done. The judge has the ability to lock you up for a year. Why push your luck? They already gave you an extension. I my county, you would be getting out of jail next year - why would your judge be any different?
We do not have a client/attorney relationship until you make an appointment, we discuss your case face to face, I accept a retainer, and we explictly agree to enter into representation.
I agree. There is so much community service that needs doing, it should be a breeze to find something. Finish it or risk jail. Here, the judge might not have even granted an extension.
Worst case is your deferred is revoked, you have the theft charge on your record and you go to jail for the maximum time allowed. Best case is a short extension. Just go anywhere and volunteer for your last four hours and get them to write a letter on their letterhead if they have it. Why risk jail over 4 hours of work. It sounds like you've had an entire year to get this done. Not many judges are going to be sympathetic to you not being able to do what amounts to less than 1 hour a week.
I completely agree with the others' sentiment and advice to get the 4 hours done. One alternative, however, that you might consider is calling the court/clerk to see if the judge accepts payment/fine/charitable contribution in lieu of performing public service. I've seen some jurisdictions allow this for out-of-state defendants or people in your situation. It depends on the jurisdiction.