This is some type of "homeowner's association" and they have a whole bunch of different numbers they use! I've tried blocking them, too, but it's of no use since they have so many numbers. I've even picked up the calls and told them to stop bothering me, but they won't give up. Someone needs to report them to the FCC.
They never leave a message and when you DO answer, they say they are from some type of homeowner's association. I've asked them many times to take my number off of their list and they continue to call me anyway. I've stopped trying to block them as well, since they have so many different numbers that it doesn't do me any good. They need to be reported to the FCC.