When my BT connection went down for a few days a couple of years ago, they immediately dispatched (I think it came through the letterbox well under 24 hours after I reported the fault!) some form of standalone wifi box to which I was able to connect while they resolved the problem at the cabinet. Can the provider not do something similar while they sort out a permanent solution? Seems a good way to impress a new customer...
Incidentally, a friend had to piggyback on a kind neighbour's WiFi for a while, it was also quite intermittent and I got her a WiFi extender which improved things no end...