Turkish Airlines Cancelled My Flight and Provided Poor Customer Service

I thought THY provided quality service, but they disappointed me. Despite being more expensive and Istanbul Airport being further away for me, I chose THY for their supposed better service, only to regret it. THY canceled my flight for an unclear 'operational' reason, acting as if the universe revolves around them. They don't offer seats on the previous or next flight because they are full. If you're so full, why cancel a flight you've already sold tickets for and received payment? It seems people's plans and other payments don't matter to them! They suggested I could be put on standby, meaning wait and maybe get a ticket. How easy to say! You should either guarantee a suitable flight or reopen the canceled one. It's not just about flying, but adhering to the planned day and time. When you call the complaint unit, they have no authority and tell you to create a file online. You create the file, and they say they'll respond in 7 days. It's already almost a holiday. By the time they respond, more time will have passed, and will a non-existent ticket be found in 7 days?! It's a complete lack of resolution!