Mtn charging me twice! Costing me R105 in bank charges!

Good day,I have a home wifi router which I took from MTN on the 31 of January 2024. On the 28th of February I went to the atm and made a manual deposit of R430 towards my month to month home wifi. This morning a debit order of R389 was attempted by MTN for the same service, now I had no funds in my account hence I opted to deposit myself. A failed debit order costs me R105! I find this really unfair as to why an amount of R389 was debited from my account.