Nightmare with installation dates

What an absolute nightmare.

I originally agreed on an installation date of the 16/12/24.

Received a message today (12/12/24) saying that they wouldn't be able to install today. Which is weird as this was never the installation date.

I've now just had another message saying installation date has been delayed til 20/1/25.

Absolutely not acceptable whatsoever. My current Internet gets disconnected on the 18/12/25 and I work from home.

What can I do? I can't get an answer out of any of their so called customer support line, least supportive thing I've ever called.

Is there anyway I can speak to an area manager?