Disappointed

I took a month to month WiFi with Telkom which they debit R449 monthly since last year 2023. I always ensure there is money in my account for when they debit hence I have never missed a debit order.

However, this month I got a notification of “insufficient funds” and was charged for not having enough payment yet the money was there. I then contacted Telkom customer service to find out what happened and I was told that the person who was gathering my invoice made a mistake and put R499 plus a subscription that I have of R19(which I’m not aware of). Now I’m told to pay an amount of R519 and might be charged for a rejection fee of R200 in August. My question is, how is this my fault because I made sure that the actual R449 was available for the debit.