My internet is bad, I don't know if the installation or the service itself. I don't know what else to do or how to complain. not solve. I call them, the problem is solved and the same day it happens again. Horrible.
Call the broadband team again and ask for full investigation including any lines that are feeding your property as well as the main lines further afield.
It could be a fault with the router, have you done a factory reset by holding the reset button for 15 seconds?