Shoptite *****s food out of 83 yo widows mouth

I am 52 years old male and have been boarded in February this year and am looking after my 83 year old disabled widowed mother. I bought about R740.00 worth of groceries (food for us) on my credit card just past 14h00 on Sunday the 27th of September 2015 at Shoprite Valhalla. The transaction showed as reserved for the store on the sms I received from my bank. The store said the transaction did not go through and wanted me to pay again, but could not show me a slip that said declined. I refused and showed the shop manager the sms. He phoned my bank's card division who confirmed that the money is reserved for payment to them. He said it is not acceptable and either I pay again for the goods or I leave the goods at the shop. I refused and offered to sign a slip stating that I will come back and pay for the groceries should my transaction be reversed. I live three blocks away from the shop. I sent my female companion to fetch the police to help me resolve this. I had paid for my groceries and wanted it, but the shop refused to give it to me and would not provide me with a slip that said my transaction was declined either. I was forced to leave without the groceries.