Channels 12 & 13 are problematic because they are not available in a number of countries - but they are here in the UK and most of Europe. If you are trading in the UK and have products that only offer a subset of the locally available WiFi channels that's a bit problematic. If you then have your customers using devices that don't allow manual channel setting, or even just a tick box in the router settings that stops it from using channels 12 & 13, then you have problems.
Mods: Vodafone not having a solution for this must be costing the company tens, possibly hundreds of thousands of pounds per year in completely unnecessary customer service calls. If the "don't use ch12 & ch13 tickbox" fix were implemented in the router WEB-UI, it's not even a setting that home users could mess up (much).
Solutions: You can try calling customer services to see if they can do something about it (I believe using an old version of the VF app used to work). Else you could a different device for your WiFi - router replacement or wire up a device as a WiFi access point. The messy way might be to set up a hotspot on your phone on channel 12 or 13, then put the phone near the router while you reboot the router and it should avoid those channels at least until its next reboot!
*Vodafone actually licensed Technicolor's "WiFi Doctor" at one point that was supposed to intervene if devices were unavailable on certain channels and then pick a different channel to fix the problem!
