Qatar Airways Date Change Issue – Booking.com Not Helping

I purchased a Qatar Airways flight ticket through Booking.com with the reservation code YKTEEL for travel on 20 April, paying a total of 450 pounds. I now need to change the date of this flight to 12 June and would like to move my existing booking to that new date. I contacted Qatar Airways customer service to request the date change, but I was told that I must contact the company where I bought the ticket, Booking.com. At this point, I am stuck between Qatar Airways and Booking.com and cannot complete a simple date change for my ticket. I kindly request that my flight on 20 April be changed to 12 June under fair and reasonable conditions, without losing the 450 pounds I have paid. I expect Qatar Airways and Booking.com to coordinate between themselves and provide me with a clear and practical solution as soon as possible so that my travel plans are not disrupted.