Inconvenience of card transaction

Yesterday I tried making a purchase at a store only for my card to get declined due to insufficient fund, This was so embarrassing as I knew I had money in my account . When I went onto my internet banking I saw a transaction for purchase at Edgar's Chatsworth 06/09/2017, I didn't make no purchases on this date. When i called the Nedbank call center i was advised it was for a card transaction i did in July the merchant didn't take the money until this month, Apparently the merchant has up to 6 months to take out money when you swipe your card!! This is an absolute inconvenience , I paid my account at Edgar's on 26th July 2017, i immediately received an sms from Nedbank when i made the payment at the store , i was under the impression the money went off my account , if i knew the payment didn't go off my account i would of made prior arrangements.

My account is currently on a negative amount , I have to incur additional charges for honor payments and installment for July . i was under the impression all my accounts where paid for the month of august , Not everyone can afford to make double payments for their accounts. I didn't plan for this !!

As a customer of Nedbank I am really upset by the service, We as consumers should be protected against this !