Sunexpress Flight Cancellation and Compensation Claim

My Sunexpress flight XQ840 from Izmir ADB to London Stansted on July 18 was delayed despite Izmir ADB Airport being open at 11:30 PM. I received an email at 1:41 AM stating the flight was canceled. According to regulations, for international flights between 1500 km and 3500 km, I am entitled to a €400 compensation for cancellations and prior delays. Since flights were not operated despite the airport being open, I am claiming my €400 compensation. No hotel accommodation was offered, and I have been left in a difficult situation. It has been more than 8 business days, although the email mentioned I would be contacted within 5 business days. No one has reached out, calls are unanswered, and there is no response. I request Sunexpress to contact me at s****@gmail.com. Please address this matter urgently.