This is not going to be better at any other ISP, there was a myBB article about it recently:
SAFibre and TT Connect in court battle over poor service levels
@OP, sorry about your bad experience, but sadly this is really out of CoolIdeas' hands. And I agree with you in regards the ISP should handle it for you, but not sure they can do anything for you. The manager should have contacted you though.
Yeah, look Cool Ideas should be hand holding the whole way - to the point that they show all exhausted communication to TT Connect over the issues.