Unnecessarily debited

I had an outdistanding fee of R743 and I had a link to pay on my WhatsApp which they sent . On the 13th of July I did pay R750 & to my surprise on the 16th they debited my account .I called and requested a refund and was told to wait for Monday . I called on Monday and I requested the money asap as I felt 14-21 days for a refund is a lot as my account was in good standing when they debited . I called and was told I would be transferred to the supervisor next thing they hang up . I took it to Facebook and still waiting to be contacted even now