Some of our customers use the 'Camtech XML' payment method which is also known as Secure Pay. This is only used in Australia as far as I know.
One of our customers who uses this reported that her payment method stopped working about 2 weeks. I contacted CS Cart and they said that it's not used anymore and it's now called DirectOne, but DirectOne isn't integrated into 2.4.5 so they would have to charge to create it.
Instead, I called SecurePay and spoke with someone in their support team advised that they had changed some of the URL's without telling anyone. He gave me the new ones so I fixed it. I have attached the updated .php file.