Turkish Airlines Wheelchair Service Issue

My spouse had surgery in Antalya. The assistance at Antalya airport was excellent... However, the experience at Istanbul airport was very stressful. We paid ₺850 to your agency for special assistance. Despite being told that everything would be taken care of, the help was non-existent. The system used to disembark from the plane did not align properly, creating a gap. Even I struggled to cross it despite being healthy. The flight attendants helped my spouse onto the elevator system. After explaining my spouse's condition, once inside the airport, while I was looking for our luggage, the staff moved my spouse from the wheelchair to a regular seat. I told the staff not to do this and questioned why they placed my spouse there like a bag before the other staff arrived. They told me their job was done and I should wait for the inside staff. I paid extra for this assistance service. Instead of the ₺350 I should have paid, I paid ₺850 because I booked through Enuygun.com. Despite this, my spouse was left in regular waiting seats like a normal passenger. I had to find a wheelchair myself, but the one I found was broken. A lady in charge of the wheelchairs saw me and, using her initiative, helped me despite objections from others waiting. Photos of the waiting passengers and my spouse were sent to the management, but nothing was done to resolve the issue. Some passengers called to complain. If my spouse's surgery is affected, I will sue your agency. I request compensation for the incomplete service for which you charged. When selling tickets on other websites, please specify your rules to prevent inconvenience to people. Charging ₺1500 for a service that should cost ₺350 is unacceptable.