Honfee of 90 wrongly charged

Yesterday Nedbank slapped me with an Honfee of R90. Recently i discovered that Nedbank debited my account with R411,75 for a transaction that had occurred in July 2019. Apparently the shop involved did not debited my bank account in July even though I received a notification that the purchase was successful and my account subsequently debited. During this week Nedbank debited my account with R411,75. I queried it and according to them it was aforementioned amount that was not honoured in July. Now yesterday Nedbank charged me R90 as my account is now in arrears. I don't understand why nedbank charged me R90. It's not like a made a purchase knowingly I do not have any funds. This is unfair for punishing me. They should be punishing the shop and not me. I'm done with Nedbank. Disgusting service!!!!!