No, as far as I am aware, there is absolutely no reason why black holes cannot contintue to accrete matter. I don't believer there is an upper limit on mass or any reason why there should be. Mass just won't compress beyond a certain point, but that doesn't mean you can't add more.
Also, there are theories that the mass-singularity at the heart of a black hole is NOT actually what's there and that it becomes a dense soup of radiation. That may or may not be, but in any case do NOT let it lead you off into crackpot land where the singularity that started out universe was a black hole. Black holes don't have THAT much mass.