THY Flight Missed Due to Staff Error and Ticket Issue

I was present at the airport for the 12:30 Gaziantep flight within the specified boarding times. I lost a lot of time because the devices did not read the QR codes during luggage delivery and no staff attended to the issue. Later, the entrance gate was changed from G2 to G5 without informing me. We continued to wait in front of G2. Despite going to the changed gate at 12:20, I was not allowed inside. Although I completed all the procedures correctly, I missed the flight due to staff and information errors. I was told that I had no chance of being on a standby list and had to buy a ticket for the next day at 01:45. No free change was made, I was not put on a standby list, and while my friend got the same flight for ₺1700, I had to buy the ticket for ₺2975. Where is THY's insurance or customer satisfaction? I request that my grievance be resolved as soon as possible. The images are of the tickets I purchased separately.