I believe that most spas have ATM machines in their facilities. You can always withdraw money out of your credit card there.
I also think that the bigger spas offer the possibility to pay by credit cards but I don't believe that the majority of us use this type of payment. So it's not a popular habit.
As of Independant providers, I'm not sure who. I use to be client of one girl, 7 to 10 years ago who was also a RMT and she was giving receipts but unfortunately she retired long time.
That would imply the person is using a cash advance to pay for escort/massage services. You should probably rethink your priorities if you are using a cash advance to fund your hobbying.