Disappointed and let down .

I have used flight center many times and have always found them very helpful, but on a recent trip , on my home ward leg from Gatckwick,Istanbul ,Cape Town with Turkish Airlines , my ticket that I'd bought from Flight Center was not honored by Turkish Airlines , so I had to buy a new one ticket home , when I asked about a refund as I had already got a ticket , Turkish Airlines said that I should get a refund from Flight Center . After emails to flight center almost every day since I got back last Wednesday , a week today , still not one answer , called today and the person I booked with is off today , another person said that he'd look into it .When i mentioned that I was happy to speak to a manager I was told that that wasn't necessary .As I use Flight center a lot , I said that I was happy to receive a voucher if they did not want to refund me . Flight center in the past have been great for me , just very disapointed this time .Kind regards,Philip Engelen.