Unjustifiable price increase and quotations given.

I recently received a quotation for flights to book for Dec 2016 return from JHB to Venice for R5 636.23 on 14.01.2016. We have planned our wedding for overseas and were advised to let our guests know this would be the estimate cost per ticket (subject to change but not by a vast amount). We have invited over 40 guests, and were advised we could put their contact details on our invites in order for our guests to get the best prices. We were advised that the prices may change because of interest etc, but now we have been quoted an amount of R8 995.23. per ticket? What justifies this huge price difference. We were not able to book tickets in advance as per advised, and can now. The price of R5 636.23 was quoted on 14.01.2016. Passport details were sent on 20.01.2016 to make bookings and payment, and I was then advised today 29.01.2016 that we can go ahead at the price of R8 995.23. I contacted the feedback helpline and they could only advise that that is just the way it is. Communication from Flight Centre has been misleading and false. I will not purchase any tickets from here forward.