We rely on three for our main broadband connection (no fibre, very slow adsl). It failed today for the second time in a week. After 10 minutes we were in touch with their "customer service" operative. Told us they had a fault. We asked when it would be fixed. Told us they didn't know but would send us a text. We pointed out that their service was down and a text would not arrive, how about email (slow adsl is o.k. for that). Replied that they would send us a text.

Gave up.

The above is fairly typical of our experiences with their "customer services" - not much sign of "making it right".

If you have no alternative then use them. If there is an alternative I would suggest avoiding them like the plague.