Poor service

I booked a flight through Travelstart in July and received the confirmation email. When I arrived at the airport in August the flight had been cancelled in July already but I had never been informed. It was a Mango flight, so I went directly to the Mango counter and was informed Travelstart needed to refund me as I booked it through them. I called Travelstart and finally got through to a person, who said it was not their responsibility. He said he would get back to me and has not done so. Such poor service.