That is a well known caveat of using Apple devices. See this topic for further discussion on it:
LinkApple is extremely driven to supporting the bleeding edge of hardware rather than support old stuff. They'll wait it out in hopes you upgrade rather than you waiting for them go back and fix. Their advertising model is based on that idea alone.
Unlike Apple, Android devices usually has two QA barriers that must be passed (First by Google then next the Manufacturer). In the cases of hardware on a carrier plan, there is a 3rd QA barrier which would be the carrier itself (Apple usually gets a pass on this due to their strict iTunes integration regulations).
Since Apple is both, the QA barrier is just one and thus have greater control what can and cannot get through. For example, Samsung may block an Android upgrade even though Google has delivered it and there isn't anything Google can do. More than likely, Apple is allowing older hardware to be upgraded just so they can say to investors at their expo events that they have more devices on the newer platform (which is what investors want to here)
You're best bet would be just to rollback to the previous iOS version you had.
[Edited by Neo7, 1/10/2015 8:45:03 PM]