Issues with THY and Anadolu Jet Ticket Changes and Fees

I joined a tour to Uzbekistan/Kyrgyzstan by purchasing my own tickets. Days before the trip, my friend B** O**, who was on the same flight as me, switched to THY by simply changing the date on his ticket without paying any extra fees. When I tried to do the same, I was told that changing my ticket would incur a 75 € penalty, plus taxes, and I would have to pay the difference for the new ticket. During this process, I was informed that Anadolu Jet had separated from THY. When I tried to access THY's website, it said the transaction couldn't be completed. On the Ajet website, I was redirected to TK, and I couldn't change my flight or ticket. Additionally, since I didn't have baggage allowance, I tried to purchase additional services, but the page kept warning me that 'changes were made to your flight.' At the airport, they asked for $200 for a 17 kg suitcase during baggage check-in. I told them I didn't have cash and would pay by credit card. They said they didn't accept credit cards and told me to withdraw money from an ATM, otherwise, they wouldn't take my suitcase. When I mentioned that I wasn't Uzbek and my card wouldn't work at their ATM, they told me to leave the suitcase. I started crying, and a Turkish friend there offered to give me euros in exchange for ₺. With that stress and sadness, I boarded the plane and later heard that many others had faced similar issues. The flight attendants still had THY badges on their uniforms. If THY doesn't take responsibility, the collaboration seems to continue.