I think there's an error in your profile. It says you had a mitral valve repair December 14, 2012 but it also says October 21?
In any case, yes, we have heard of mitral valve repairs failing and often when they fail it is not too long after surgery.
I am very sorry to read your valve is failing but I don't know anything about a too large band causing failure.
Your surgery was at Cleveland Clinic?
So sorry you have to deal with this.
Best wishes.