Travelstart lack of accountability

I booked a return flight from JHB to CPT via Travelstart for 02 April return on 03 April- the funds remained uncleared on my card and i received no confirmation.I send various e mails but Justine failed to respond-out of desperation I booked and paid again on 01 April-Travelstart do not want to refund me thus i paid twice for flights. They allege they are not liable airline is? My agreement are with them as the facilitator-you can not phone them and get random e mail reply.