Check your credit card statements!
I was charged for a May stay upon booking it in March. I thought it odd but I let it go. Then at the end of my May stay I got charged again, albiet a different amount. As soon as I spotted this, I contacted the hotel. While I was on the phone, I got a notification from Marroitt Bonvoy that the erroneous March charge had been reimbursed. It was that easy. They apologized and explained that they have a new computer system and many of their customers are being double charged. They were very kind about it and as I said, I was reimbursed within minutes.