weather has knocked out my Sky tv before because it is satellite but I have never had any weather related disruption to my VM service. It tends to be quite resilient because the majority of the cabling runs under the ground. I don't know about the 789 number but when you ring 151 and select the option for tech support, one of the option allows you to check for "known" area faults. The only problem is that if you have a service outage and ring immediately, they will be unaware of it and it won't be on the automated system. Furthermore, they like to deny that anything is wrong and it is only about 2 hours later when everyone else rings up (and sometimes not even then) do they register it as an area fault. They tend to like booking techs out to give everyone new modems
I take that when you say "was down for 14 hours" that it is now up?