[General Maximus]

If you need to book a 3rd tech out you can tell them you want to put in a complaint when you do it and you want somebody more senior to look at it (the principle technician). It isn't good enough to say that they can't find what is wrong. If they can't find a problem close to home then they need to be looking elsewhere or escalating it to someone who can. If they say they have checked and there isn't a problem on the network then you can tell them you want them to start swapping out equipment by process of elimination such as the cables, the connectors on the cables and the shub. Noise isn't the problem here, that would be reflected in some dodgy power levels, it is a dirty or faulty piece of equipment and could be something a trivial as a loose or dirty connector on the outside of your property but likewise in the cabinet.

If I were you I would clear those rs errors from the log and see how it goes over the next couple of days. If the cabinet has been report to networks it would have been sorted pronto and the weather has been nice over the weekend for it to dry out. I imagine they will have replace any wet connections so now is a good time to see if whatever they have done has fixed the problem. If not, make another phone call.