Ajet Refused to Refund or Compensate for My Brother's Canceled Flight

We purchased tickets through Ajet for my brother and his wife. The itinerary was from Dalaman to Ankara, and then a connecting flight to Erzurum. However, when they arrived in Ankara, their flight was canceled. We requested compensation or a refund for the canceled flight, as we are entitled to it. Despite providing all necessary booking details and proof of purchase, we have received no proper response from the airline. I experienced a similar situation in the past, and I received the necessary refunds. However, they claimed that no compensation or refund is provided for canceled flights, which is unacceptable. The lack of clear communication and accountability has been frustrating. We are asking for our rights and would like them to contact us regarding this matter.