Turkish Airlines Istanbul-Adana Flight Boarding Issue

On 15.08.23, our Turkish Airlines (THY) flight from Istanbul to Adana was scheduled for 15:30. I had already checked in online and we arrived at the airport at 14:20. When we tried to drop off our baggage at 14:50, we were told that the baggage would not be accepted. We requested to speak with another representative, who also informed us that our baggage would not be accepted and that we would not be allowed to board the flight. At this point, it was still only 14:52 and I was planning to leave my baggage in storage. However, my spouse, daughter, and I were directed to purchase new tickets instead of being allowed to board. Despite having completed the online check-in, we were not permitted to board. We were pressured into purchasing new tickets before 15:30, otherwise, we would have to buy them at a higher price. According to THY's own website, passengers should be at the gate at least 25 minutes before departure. My second ticket or the initial ticket that they claimed was void should definitely be refunded. We explained to them that we were trying to rectify the situation and that purchasing a second ticket would put us in a difficult position, yet our check-in was not reconsidered.