Travelstart lies

I booked a flexible ticket which allowed a change in date with Travelstart for 8 March 2022. My reference is ZA***6. I realized that I needed to change the booking and used the website, app and call center but received no support. On 7 March I used the website to move the ticket to book for 23 March and I took screenshots. I was told by the WhatsApp support that there was an additional cost of over R200 . I paid that. A ticket was emailed to me. I did not receive check in details on 22 March. I drove to the airport and found out from the airlines that Travelstart had **** and did not make the booking for me. I requested a refund. I was told they would get back to me I have heard nothing. This has been a horrible experience. This company has **** and cheated me out of over R2500.