Double debit.

I'm very upset. I tried to make a manual payment on the mtn app which I had thought didn't go through for R811. I attempted again with an amount of R810. On the 14th of March an amount of R811 was successfully taken off my account. However on the 16th an amount of R810 was attempted to be debited. Due to insufficient funds it was not successful and I was charged R120 for a returned debit order.

My irritation comes in that fact that Mtn is not acknowledging my payment of R811 and are not acknowledging the attempt of double debit.