They made an update on the support page
https://na.wargaming.net/support/en/products/wows/article/10214/
It says:
Should you want to dispute a chargeback, Player Support won’t be able to provide further information about the reasons behind the chargeback.
I'm starting to suspect they have some kind of issue with their payment platform, Adyen, that triggered a chargeback request. This platform is used by many big companies like spotify, microsoft, ebay,... I'll wait a few more days to see if the money gets on my bank account.
Unfortunately noone else seems to have had a similar problem so far.