Woolworths

Hi,
I'm writing this complaint not waiting for anything back but only to give feedback on my shopping experience.

I went to shop a detergent and a salad to woolworths with my friend, and he went with me to buy some groceries for lunch. I came in, grabbed the things and paid for them. I chose not to print the receipt because I never do it since I don't like to waste paper. I left the store and went to the chemist located in front of woolworths and while I was there my friend who was still inside woolworths called me asking for help to choose the right beef for his meal, so I went back in to help him. We chose the ingredients and paid for them.
When I was leaving the store, a woman who I believe was the manager, was staring at me. She stopped me and asked me to see my bag. I showed it to her and she grabbed the detergent and the salad and told me: do you realize this is our product?
I told her: yes. I bought them. I bought them, went to the chemist and came back to help my friend.
Then, she said: I need to see the receipt
I told her: I did not print the receipt, I didn't realize it was required to print a receipt, considering that the self check-out gives you the option not to.
She said: why would you do that? Do you realize what I'm trying to say? I can take this from you because you do not have a receipt.
I said: I can show you my last bank transaction if that helps
She said: No, you are telling me you bought this and then came back again?
I said: yes, am I not allowed to do that? You can check the cameras and you'll see that I paid for these products.
She said: I feel like doing some good deed, so I'm going to let you go with what you stole.

I left the store feeling embarrassed, as everyone in the store heard when she affirmed that I stole products that I bought.

If printing a receipt is mandatory, I recommend you take the option out of the self check-out or at least put up a sign that says that you are not allowed to come back if you already purchased something