We had very unreliable cable internet with Suddenlink in rural California. For a few years though, when I called I'd be connected to some guy who knew what he was doing and would have an intelligent conversation with me to identify the problem. That was nice. Then it all changed and I started reaching the generic front line support that had no clue and was just trying to find a way to dismiss your call.
Then it all changed again and when our internet was out for 2 solid weeks, they didn't answer the phone at all. The bill still came though.
Speaking generically, whenever you run into a clueless front line rep, I'll encourage everybody to just be patient and polite until they get you to the next level. My sister used to work phone support for a retailer and there were days when she had to go to the restroom to cry. It can be a stressful job because they get a lot of people who think they can get better service by being irritable and nasty. Of course there's rare exceptions where the rep themselves wants to have a fight, but that's usually not the case.
I think the worst "support" experience I can think of wasn't with a computer company, it was with U-Haul. I have no idea how that company is still in business today. Back in the 90s and 2000s they were hopeless. They basically never had anything you reserved. They'd take 15 minutes to print a receipt for each customer, sometimes send last minute "updates" requiring you to drive to another town to get your trailer, or alternatively making you wait while *they* drove to another town to get your equipment, etc. It was as much fun dealing with U-Haul as the DMV. I think they're a little better in the last ~10 years but still pretty bad.
One of the worst experiences was with this dumb variation of their tow dolly that doesn't have proper ramps on it. Instead the back end of it just drops down and you have to drive up a very short, sharply angled ramp. No car can use this because the overhang from the front wheels to the front of the car just hits the ramp before the wheels have even reached it. Maybe a truck can use it, but not any realistic car.
We got screwed with one of these, having told them exactly what car we were towing at the time of the reservation, and there was just no way it could get up the ramp. Drive back to the facility, hours wasted. They had several of the proper style of dollies at the facility but they refused to let us swap it. So then it's time to get out the phone and call UHaul Central. Time to start arguing about why we can't use their cheapass dolly and need the properly designed model. They insist that if the car won't fit then it must have been "modified". No, it's stock, it's exactly the car we said it was for the reservation, and hardly any stock car made in the last 30+ years could ever use this thing. They flat out refused to resolve the problem, acting as if we had picked the dolly and not them.
About a year later the same exact issue came up again with a different car. That time the rental place was a smaller outfit (a UHaul affiliate/franchisee/whatever). He gave us a refund which was all he could do since he didn't have any other dollies. He was as annoyed with UHaul as we were. I like to think he probably complained and somebody at the company might actually listen when it's an affiliate making the complaint, instead of a lowly customer.
Few years later we made the mistake of reserving a truck from UHaul for a move. They gave us a shorter truck than we had reserved. We had to leave a lot of things behind because of that.
We dealt with Penske once. They seemed way better in that experience, better organized, and at the same time easy going and accommodating. When it came time for our move they were willing to price match against UHaul. It was a huge mistake that we didn't take them up on that because I bet they would have had the correct truck, probably sitting in the parking lot pointed out with the engine idling at the crack of dawn on moving day. Instead we had UHaul.