The kWhs charged for gas on our bill don't match the difference in readings?

For the last 3 months our gas bill seems to be increasing huuuugely. For £80 usage to £200+ usage in a month! Nothings changed though. 
 
I thought I'd analyse the invoices a little closer and it looks like we're being charged 10-12 times more than we've actually used. This has been ongoing since we were moved from to Ovo 14 months ago. I've tried on chat to discuss but they were useless so we'll have to call between 9am and 5pm on a weekday. Not handy for people who work those hours! 
 
Can someone take a look at the screenshot in the feed to double check I've not read this incorrectly? I've checked the electric and what's been used is what has been billed.