Generally, most of the payment processors, they only care that a valid transaction was broadcast to the network within the timeframe that they show the invoice as being "valid"... They will generally just not process your order or credit your account until that transaction is actually confirmed.

Any service that issues an invoice for say "30 minutes" and expects that a user can guarantee confirmation in that time frame (regardless of fee paid) is asking for trouble. As you saw, there can indeed be time periods where a block is not found for over an hour!

Sometimes, miners are just "unlucky"