lousy tv service

we have been with Xfinity for 6 years now and been having problems with them continually. The most problem we are having is our tv service stalls or the tv goes black and we have no tv from anywhere of20 seconds to 15 minutes.I have checked to see if there are outages in the area  but supposedly all is okay.  If this happened one or twice I wouldn't be concerned, but this happens at least two or more times a day.  Calling in is a joke, if you happen to get to talk to a person,all they want to do is reset the service which does nothing and that is all they will  do to alleviate the problem.   Another problem is with my tv resetting itself while I am watching it.  It is not one tv it happens to all of  our tvs.  The cost of the service is outrageous for what we are receiving.  What can we do to get the type of service for which we are charged?