Due To a Restroom Break, I Missed Turkish Airlines Flight Boarding

I was let down by THY! On the morning of 25.08.23, with PNR number tbtu**, I was on the 8:20 Istanbul-Paris flight. While waiting at the gate, I went to the restroom due to feeling unwell. Boarding was still in progress, and I returned within a minute. Upon my return, I was told that boarding had closed 9 minutes earlier. My girlfriend and I were left at the gate. Despite security cameras showing that the gate could have closed only a minute before, THY staff provided false information and offered no assistance. I was directed to customer relations, ticketing, and the Supervisor section for a change/refund, but received no clear response or solution. Consequently, we missed the 10:05 Paris flight as well. Furthermore, since we were not allowed on the outbound flight, my return ticket was also voided. Due to the cancellation of my first ticket, the second one was automatically canceled, causing significant inconvenience. I request that Turkish Airlines, as a reputable company, allow us to use our return ticket from Paris to Istanbul on 01.09.23, which we paid for, and help alleviate our inconvenience.