Airtickets expiry due to FASTJET admin problem

I booked 2 airtickets online, Johannesburg to Dar es Salaam. The booking expired 11 Sep 2015 at 13H26.<br> I went to the booking office as there was a problem re credit card payment method, they said they (Joseph in Mwanza) would extend the expiry date.<br> the initial booking was for 1,400,000 Tanzania Shillings, now they did not extend the expiry date and the ticket is over 1,600,000 Tanzania Shillings!<br> <br> I demand a refund of the extra 200,000 Tsh as it was their mistake and not mine!!<br> <br> My email address is [Email Removed]