Yes, in the moment I ordered a GPU instance with per hour billing an invoice for about 1 month of that instance was charged as "credit". They say I did it, but at no point I filed such order, and if I did, at no point that amount was shown to me.

Maybe a bug or some UX/UI shenanigans, since I also got errors to cancel such invoice and obtain a refund. But since I complained through PayPal they've been acting in bad faith (like contesting my dispute the very last day without getting back to me, or changing the reason why I I'm not eligible for a refund).