Why is telecom customer service so terrible?

Hidden fees, they don’t show up, the modems they give you are terrible, connections die constantly, customer service is absolutely dire.

Is it because of deregulation?

There are plenty of regulations.

How many suppliers of those services do you actually have to choose from?

https://mises.org/daily/2139/Who-Owns-the-Internet

“Is it because of deregulation?”

Neo-liberals

Obv.

As Daniel pointed out, there are PLENTY of regulations. Here in Brazil as well as in the US, there is no free entry in the market for those types of companies. So there you have it, a monopoly.

It’s important to note that monopolies have nothing to do with the number of service providers in a given market niche. It has to do with whether people are free to offer their services or not. So you could have only one provider in a given niche and don’t have a monopoly, and you could have 20 providers and have a monopoly. There’s no way to know the optimal number of providers in a given market if the entry is blocked by government intervention.

That said, enjoy: