This isn't a complaint. I thought I'd share my own experience with Verizon and their customer support. For some context, we started off with Comcast. The cable or TV would go out a lot. Service calls were put in, and (almost without fail) the service person would either not show up at all or they would show up hours after the scheduled service window. I'd be on hold for long times, waiting for a supervisor - only to have the call dropped or hear that he would have to get back to me. However, the return call never came. The final straw was one entire week with Phone, TV, and internet down - and service dates at least a week or more out.
That's when we switched to Verizon. The difference was like night and day. The system hardly ever went down. If it did - they were either able to do something at HQ to fix it or a service person was scheduled, came on time, and fixed the issue.
Supervisors did get back to you.
I've found the main time issues surface are around changes. Adding/removing services, etc. Occasionally, the person on the other side of a chat will give you incorrect information. But for the most part, it's been good.
It sounds on here like there are a number of places in the process that have failed. Incomplete deliveries, weird bill issues, and speeds that aren't what they are supposed to be. Document everything, get the names of who you spoke to, the time, and any case numbers. Be sure to have that all handy when you escalate the issue to a supervisor. They've got a number of channels to contact them. If one doesn't work, try another. Maybe have stores in your area where you can go to get equipment if the right parts aren't getting shipped. If you're on hold on the phone for over 10-15 minutes or keep getting transferred, hang up and try later.
Anyway, if this is the first time you've dealt with cable service and things aren't going well - trust me, it could be a lot worse. Hang in there, it'll get better...