I Face Unauthorized Refund by Booking.com and Lost £875.99 Return Flight Ticket

I booked a return flight from Doha to Toronto and back from Toronto to Doha through Booking.com under customer reference 40-678159884, with ticket number 512-9085949862, for which I paid £875.99 GBP. The outbound flight from Doha to Toronto was scheduled for 27 March 2025, and the return journey from Toronto to Doha via Amman (YYZ–AMM flight RJ272 and AMM–DOH flight RJ650) was originally scheduled for 11 April 2025. I used the outbound segment from Doha to Toronto, but due to an emergency, I did not use the return segment from Toronto to Doha. Because I could not take the return flight, I contacted Royal Jordanian on 6 April 2025. Royal Jordanian confirmed that my return booking was cancelled, but that the ticket was kept open and could be rebooked until 26 March 2026. Relying on this information, I contacted Royal Jordanian again on 14 December 2025 to rebook my return flight from Toronto to Doha, and at that point, I was informed that my ticket had been refunded by Booking.com on 15 August 2025, without my knowledge or consent. I have never requested or approved such a refund, and I was not notified about it in any way. After learning this, I tried to contact Booking.com via the phone number 1‑888‑850‑3958, but I was only able to reach an AI system, which could not locate my booking and did not connect me to a human agent or offer any solution. At the moment, I am left without a valid return ticket and without any clear information about what has happened to my booking and to the £875.99 GBP I paid. I prefer to receive a refund for the unused Toronto–Doha segment. I kindly request Booking.com urgently clarify what has been done with my ticket 512-9085949862 and the payment of £875.99 GBP, to provide a full refund to me if it has not already been transferred to my account, or otherwise to offer a fair and transparent solution that compensates me appropriately for this situation.