No service with Turkish airlines.

I had a flight with Turkish airlines from Ulaanbaatar to Istanbul on the 16th of August 2018, TK 343, which ended up being delayed by more that 15 hours. Subsequently I missed my connecting flight with a different airline and my first night in a non-refundable hotel stay in Athens. I’ve tried to contact the airline twice via their website, but have had no response as yet. I’ve also tried to ask at the check in counters for my ongoing flights, the supervisor counter at Istanbul airport, etc. but no assistance or help have been forthcoming. They all refer me to a pamphlet regarding my passenger rights, a phone booth that never answers the phone and a website that does not respond to queries. Apparently with Turkish Airlines there is no passenger rights or customer service.