On line ticket purchase - Doubble billing

I purchased a ticket on line on 06 May with their SID System. Double deduction of air fair went off my account. Contacted them immediately - spoke to Chantal, emailed her with detail and bank statement of which se confirmed receipt. Next day Sipho mailed me requesting same - this was resent. Today I call, the call centre at Mango Refunds needs to know why I want a refund - repeated entire story again - Still no reference number from them. No Super Visor is available (No surprise at a call centre) I get transferred again and yet again have to repeat the entire story to Nolizwi who in the end asks me, \why do you need a refund"- SHOCKING to say the least. I am wanting one of the payments refunded as I fly tomorrow as well as the interest they are now gaining on money which does NOT belong to them!!! MOST DISGUSTING SERVICE EVER. This is the first and the last time I will ever make use of this airline!!!!"""