Turkish Airlines Flight Booking Issue

I purchased a ticket with THY for the 10.10 AYT-Istanbul and Istanbul-Napoli flights. Due to a mistake, my Istanbul-Napoli flight was booked for 11.10 instead of 10.10. I revised it to the correct date and paid the difference, requesting that my return flight remain unchanged. Because my AYT-Istanbul flight was delayed, I was moved to an earlier flight to ensure I could catch the 17.20 Istanbul-Napoli flight. However, during check-in, it appeared that this change was not updated in their system, and my ticket was marked as open, assuming I missed the 14.30 flight. Due to their error, THY did not assist me with my return flight, which was also marked open. On 12.10, during the Napoli-Istanbul check-in, an agent informed me that I did not have a ticket for the flight and that the next available flight was at 19:00, requiring an additional fee. After being kept on the phone for half an hour, which caused further delays, the check-in closed. Fortunately, an Italian ticket agent helped me board the flight despite the check-in closure. THY's lack of assistance caused significant inconvenience. Despite paying nearly ₺33,000 for the ticket, I am struggling to get miles credited. While the AYT-Istanbul and Istanbul-AYT segments are recorded correctly, the Naples flights show no matching ticket number. This issue, caused by THY, is not reflected in their system, and they are not helping resolve it. They only sent a meaningless apology email. This experience has made me extremely dissatisfied with THY for the first time.