Wifi credit question if power failure on site?

If you are on a CC site, buy wifi time and log in, but the site then has a power failure and you are unable to log out, the wifi time clock keeps ticking away and you could end up paying £5 for 15 minutes. 

How would you be able to claim and from whom as a credit may not be much use if you are not going to be using the wifi again for sometime.  Under sale of Goods Act is your contract with the CC or with the wifi supplier as the routers and masts are on CC sites and the CC has obviously paid for the installation?

The above is a real life scenario and happened to people over the last weekend where the warden came around telling people to use their gas heating and not electric.