Travelstart - refusing to refund double payment

Travelstart are not refunding me for the online credit card payment i made for my daughters return flight to NMMU in PE on 29th March 2021.. They cancelled the booking without explanation and i was forced to pay again using my daughters debit card. I even provided Travelstart with details including " their own Merchant bank authorization code(766932) but they still have not refunded me?. In Travelstart's system the booking is still showing as "processing" despite the flight being on 7th April 2021? Booking ID GO***1 Really disappointing!!!!