Turkish Airlines Flight Cancellation and Refund Confusion

I purchased a same-day round-trip ticket from Istanbul to London with Turkish Airlines. I missed the outbound flight and bought a new ticket for the next available flight. I called customer service to request a refund for the missed flight, and they informed me that I would receive a refund of ₺3200. When we went to the counter in London for the return flight, we learned that the return ticket had also been refunded. When I called the call center, I mentioned that I had not been informed that the return ticket would also be refunded as per the rules. It is unacceptable to inconvenience people to this extent, disrupt their plans with unreasonable rules, and cause financial loss. At the very least, the full amount of the return ticket should have been refunded. I strongly advise against purchasing connected round-trip tickets. Additionally, Turkish Airlines customer service suggested that I contact the agency firm. They said 'they will help,' but I couldn't reach anyone and was kept waiting for 60 minutes.