That's great that you finally found a way to get it sorted!

Luckily, the deal I have with my ISP is that if the main landline connection ever goes down, they turn on unlimited mobile data to a little box they sent me, so I still have an internet connection no matter what. They have recently come out with an upgraded version of this deal which includes a new broadband router that has this capability included within it, and it switches on automatically if the main connection goes down. I haven't upgraded to that yet, though, as it costs an extra £10 per month.