I've heard horror stories in the past about television networks denying their content to service providers. What happens is that a contract expires between, say, HBO (or its parent company) and Dish Network. So HBO is no longer beholden to previous terms and wants more money or whatever and, until Dish Network coughs up the demands or they meet somewhere in the middle, Dish can't broadcast HBO or any of its subnetworks, etc.
Thankfully, the former hasn't happened to me (and the latter, where a channel moves to a higher-tier plan, has only really happened with ESPN, I believe).
CBS is in the midst of contract negotiations that have extended past the deadline with AT&T. So, as of the end of this past week, we no longer have CBS or any of its affiliate stations (major affiliates were supposed to be exempted from this but it didn't happen) on AT&T, Uverse, DirecTV, and DirecTV Now. Blackout City, y'all!
I contacted DirecTV Now to complain, especially since being able to view CBS shows was one of two primary reasons we selected the service (the other being wanting to watch live TV, which is also affected by the CBS blackout) and they're giving us a credit on our service for the next two months.
Two months. That doesn't bode well for negotiations. Both are big corporations and it's not likely that one can bully the other into submission. They're gonna keep fighting and we, the viewer, will pay for it all. As we always have and always will.