So, here is the situation, yesterday I tried to purchase Cuphead, but Paypal payment method was in an endless loop of failings. At first I was aware that Gog recently have some issues with that, but now I think is Paypal's fault completely.

I don't know what's happening. Now in Paypal I have a payment to Gog and a refund for the same amount without doing anything. With a delay of several hours after trying that purchase, failing in every attempt.

The money didn't come back yet to my prepaid card, I'm just waiting on that, I hope come sooner than Cuphead offer expires, because I don't have much more money.

No order pending, no refounded orders, no receipt of any kind, or new order on Gog's side or my profile, just an email for a payment and Paypal's activity feed with that payment and the refund.

Is this a normal procedure at all?, I need to do something?, or just wait patiently, I don't want to bother Gog support team for nothing.

I'm completely lost here, don't know what to do.

The Gog team are very helpful and will be pleased that you wish to purchase something. Really, they are very nice! Just drop them a line, because your experience is not normal. :)

I had similar issues yesterday and this worked for me:
1) Put the game in the shopping cart.
2) Opened second tab with PayPal and logged in directly.
3) Now I went to pay for the game and upon selecting PayPal, I didn't have to enter the password (because I was already logged in) and the checkout succeeded.

Maybe this'll help until GOG addresses the problem.

Thank you everybody for make suggestions, is very helpful.

Finally I have some update, if that helps others in similar odd situation.
After contact the support team, they contact back just in no time, very fast and effective (10 of 10 for support team). They confirm that the problem was on Paypal's side that day, and every payment was returned automatically by them.

In my case has take three days to have the refund back, using Paypal with a prepaid credit card.

So apparently it was a thecnical trouble on Paypal that made a payment incorrectly, not processing the order like should be. Support team told me that should be OK now as Paypal fixed it.

Any way, I know Gog doesn't save or use critical data from paid cards, so from now on, on Gog I will pay using my card directly.

Thanks to support team, for next time (fingers crossed) I will contact them on any issue. They are an added value for Gog, now I know.

De nada! :)