Approved vs Declined

I have now had enough of this store. Its gradually getting worse and worse. I get to the store on a Sunday, do my needed shopping and get to the till. All is still ok. Make my card payment and then all hell breaks loose. My card is approved. The Card machine shows approval but the cashiers till reflects declined. Now i have been patient but my patience is now wearing thin with the fact that staff refuse to be helpful and there are no store owned managers to assist in the store as well. I was told to make a payment again but i am not going to make a payment again as it reflects paid and i dont have the amount to put through again and making the same transaction again will reflect as ***** at my bank. I am sorry but Food *****s market Cradlestone will never see me again