Payment declined



I use Revolut frequently and usually it works quite well. Yesterday I had the following issue which I haven’t had for quite a while.
I topped up 50€. Later on during the evening I wanted to pay a bill of 17,80€ so well within my limits.
The payment was declined twice with the reason insufficient funds. After the 2 attempts my account shows -28,12€. What happend? In the end, my friend hat to pay the bill for me as I didn’t wanna try a 3rd time. Even if the 17.80€ would have been deducted twice I should have been able to pay. Does anyone of you had the same issue? How do I get my money back?