Talktalk broadband outages

My aunt is having issues with her Talktalk broadband.

She moved house and basically trying to save money got Talktalk broadband as they were offering cheap calls, free install (it had Virgin previously) and Quidco. I did warn her that they had poor customer service.

Their broadband regularly goes down for up to a couple of hours at a time, they've had multiple new routers, visits from openreach etc but doesn't get any better. She seems convinced that their router is the issue but I was thinking it's probably the new wiring or TalkTalk equipment at the exchange.

I do have an Linksys router that I was going to give them instead of ebaying it but wondering if anyone had a similar experience with TalkTalk broadband.