Never again!
Never book with this company, they're a scam. I paid THB 639,00 for a ticket, but decided to reschedule or possibly cancel. So I was referred to a phone number and told that it was the only possible way. Next I tried calling this "customer service helpdesk" and found that is occupied constantly (and I called a million times over the course of 3 days). Taking people's honestly earned money for profit like this, I would like to call it disgusting but that is a big understatement. @Sales, if you are reading this: you owe me money!