Your last sentence is key here! "hopefully the information provided will be easy to understand".
What they did in that report (13 Jan) is include unaffected days which completely skew the figures. They tried to show a 3% increase but the 12% increase from unaffected trading days at the start of January completely boost this number. Taking the trading update on 8th Jan and subtracting it from the one you provided shows a 14% decrease against prior year for the effected period. It's all here:
That is only against prior year, when you add in the growth rate it is actually even worse, a >20% decrease in transaction value.
If they separate out only impacted days, I expect the report on Monday to show a decrease of around 15% to prior year. I'm not that optimistic, however, most likely will be they will keep reporting the whole of Jan and lean on the unaffected figures to show everything is ok.
Unfortunately they are not as transparent as a company can be. And their reporting thus far has been trying to hide the issue for people who don't dig into the detail of their reports.
(20min delay)