This doesn't surprise me at all. Service under Altice has been horrific.
I was never a fan of Cablevision, they were always hostile to Huntington, but once they rolled out Optimum, I have to say the service was rock-steady. It was a delight to just have the speed I needed, the connections I needed and not once wonder what the hell was going on.
Literally since Cablevision became Altice, my service is all over the place. My wireless connectivity stinks. Every night around 7-8PM, anything remotely streaming lags. We changed nothing in our house, and it's just 2 people. We're supposed to be getting the 200 level service, and it's worse than the old 100 mid-tier service Cablevision offered.
Altice's customer service is also useless. My cousin, stupidly, took in my mother's old phone number (instead of setting up a second line for my mother. Now that my mother is in her won apartment, Altice not only can't figure out how to disentangle my mother's old number, but keeps calling ME because my mother gave Altice my number as an emergency contact until they provided my mother with a new number, and Altice doesn't even update their records. So while my mother gave up getting her old number back, and told Altice this, Altice keeps calling me about arranging to get the old number back and I can't even call them back because my number is NOT on my mother's account and there is no way to bypass the automated system.
Cablevision, at least, had competent customer care.
The only things making me more salty these days are the possibility of switching to Verizon, which I loathe, or Altice mis-managing themselves into being acquired by Comcast, which may actually be a worse scenario than Verizon.
Altice should have just let sleeping dogs lie. Cablevision may not have been perfect, but it was still the best option when weighed against the heavy hitters.