Your line problem will probably follow you to your next ISP, but hopefully they'll have half-decent techs who can actually get it sorted for you
It doesn't take 5 days to generate a MAC, it's simply a time limit for the ISPs to provide it to you -- it only takes a moment to get the code. Unfortunately, some ISPs, including the now-infamous Pipex, like to forget about it until you remind them, as though the five days is a target rather than a limit
If they haven't given it to you over the phone, they'll probably e-mail it