When a channel provider (those who sell programming to folks like Mid Rives) has their contract end, they renegotiate always for more money from your local provider. That's more money for the same programming you were watching the day before.
Mostly these negotiations go smoothly and life goes on and you never notice. Sometimes the people selling those channels want so much more money that the local provider says "whoa!" that is way too much, we'll give you less. That's when the sellers pull their programming in an effort to get you (the consumer) to call and complain and put pressure on the provider. This ensures that the seller gets closer to their asking price.
This is capitalistic greed run amok. It's extortion and completely unfair to the consumer and the reason the bill goes up every year. The sad thing is that these providers get plenty of money from advertisers as well so the extra extortion is just plain ridiculousness and greed.
Don't blame Mid Rivers. They are trying to keep your bill down...so you'll stay with them.