Unwillingness to refund promptly for website error

I'm extremely upset. I was trying to purchase a ticket for December and I paid using the SID payment option. My payment was successful and the money came off of my bank account, however the page refreshed and said that there was an error with my booking. I called in and the agent I spoke to advised me that they wouldn't be able to issues me the flight even with proof of payment, die to the fact that I'm on vitality. She said that I would have to repurchase my ticket. She also said I would have to fill out a refund request and it would take 6-8weeks for me to get my money back. This is obsurd as the entire issue was due to a technical issue on the kulula website. Please could I get some urgent assistance.