Turkish Airlines Tried to Charge for Flight Rescheduling After Cancellation

I recently traveled to Diyarbakır with Turkish Airlines for a funeral, only to encounter a travel fiasco due to weather conditions. The return flight, scheduled two hours before departure, was abruptly canceled, and I received a notification via SMS. Urgently needing to return for work and medical reasons, we attempted to change our flight, but given that there were no available flights from Diyarbakır within the next 24 hours, we requested a cancellation instead of a change.

To our dismay, after we canceled the flight, Turkish Airlines informed us that we had used our one-time right to cancel, and now we had to pay an additional ₺1800 for a new ticket on an extra flight they opened up. This ordeal forced a 72-year-old seriously ill passenger to endure a 3-hour road journey from a different city. I have exhausted all available channels for resolution. Ticket No: 2352211258385