What is your average payment history VS. this payment? When you signed up they asked you your annual sales and estimated CC charges, it’s likely you have exceeded both.
I had this happen to me with intuit years ago. They held it for 21 days. I couldn’t hold the project up and I knew it would clear so I went ahead and just ordered the equipment. When I signed up for square a few years ago I was able to get a form from intuit to prevent this from happening with square.
All of this being said. I now no longer accept credit card payments over $2500. Happy to take CC payments for a 4% charge. That charge offsets most points cards so clients just pay via check.
The Bitterness of Poor Quality is Remembered Long after the Sweetness of Price is Forgotten! - Benjamin Franklin