Charged twice for a rental deposit

My credit card was debited twice on Friday 14 June 2019 due to an error by the consultant assisting me at King Shaka airport (I think her name was Amy, if I recall correctly). My card was debited for R3 700 and for R3 349.41. I was told by the consultant that she would request for the amount of R3 700 to be reversed and that this would take 24 hours, including weekends. I called customer care today (Tuesday 18 June 2019) and was told the reversal could take 10 - 30 days! So I must get charged additional interest on my credit card due to your staff member's error?