Credit card (mastercard) suddenly not doing certain transact

2
Weird issue. Sub payment, no problem, I just manually do that every month. But for some reason I just cannot books or doujins anymore on this site.
For testing I bought one directly from Irodori and no problems there. (I prefer to have everything in one place so that's why I enjoy buying other publishers works on Fakku instead)

I've already contacted support and they were really helpful but sadly nothing seemd to fix it... I contacted my bank and even the mastercard people and they told me nothing was wrong it.

And no worries, this isn't to shit on Fakku support (got response very fast <3 )
But I'm hoping others mayby had similar issues? Or that we can find a way to resolve this. :(
I wanted to treat my self to Homunculus' latest book 😭


I've never had any issues with any cards before so I'm really in the dark with this