Immediately cancel your account and switch. If you are forced to use them as an ISP due to municipal/geographical regions complain to your city manager.
The only way to slap these companies back into line is with your wallet. If you can't do that then a couple complaints to the city manager can go a lot farther than you think, especially in smaller areas where there isn't a lot of support staff in city hall.
Considering just how big the outcry was over ISPs delivering advertisements instead of an NXDOMAIN response, and how many ISPs are continuing to mess with DNS over ten years after the execrable practice started, I haven't got much faith in the power of the market. Has there been just one ISP that stopped hijacking DNS over customer complaints?
The only way to slap these companies back into line is with your wallet. If you can't do that then a couple complaints to the city manager can go a lot farther than you think, especially in smaller areas where there isn't a lot of support staff in city hall.