It's happened to me, but not using Paypal. Also if you're not using paypal funds you should really be using a credit card or your bank's credit card, since paypal's exchange rate is borderline scammer.
Okay so then it's definitely on their end.
Yeah I've thought about switching for that reason, just haven't been able to convince myself yet since I like the added security with PayPal.
This happened to me too, but I never got an email saying the payment went through, only one saying it failed. I contacted GSC that same morning but they still haven't replied. Hopefully I'll be able to send the payment through some other way.