Turkish Airlines - flying to the most destinations badly!

We booked and paid our tickets in November 2018 to Dubrovnik via Istanbul. Scheduled to depart on Tuesday, 18/6/2019. The Monday was a public holiday in South Africa and on Friday, 14/6/2019, Turkish Airlines unilaterally decided to cancel one leg of our return journey from Dubrovnik to Istanbul. They have disrupted our holiday and numerous emails later we still have no clarity on our return to SA. Used to think they were good, but not anymore - maybe they should stop bragging about how many destinations they fly to and rather do less better!