Spar grassy park, I want refund!

This morning I bought food to the value of R897 at Spar Grassy Park. The transaction went off on my account but did not go through on their end. I was told it could take up till 72 hours for the money to reverse and that if it doesn't reverse, I have to get proof of payment from the bank. What bull****! I used the money to purchase food for my family now we are sitting without groceries while my money was taken!