Smoke City ripped my husband off 20.75 Decatur Texas

first of all, this lady wasn't the one to come in and purchase these items. He had already left the shop and returned home. I would say maybe an hour later (I'm not too sure of how long it was that he had left) the wife decides to call smoke city. The register clerk picked up the phone and she asked to speak to the manager (which was me). She stated over the phone that her husband purchased some chewing tobacco that had amounted to twenty something dollars. She told me that her husband had given the register clerk a 50 and 20 dollars. She said that her husband figured it was 2 $20 bills. Now, I looked into the register to see if there was any 50 dollar bill. There wasn't any. I tried to reason with her but she refused to listen to anything. I told her that I couldn't refund the money to her because there wasn't any proof that her husband had given that amount of money. I didn't want to be short in the register either if she was lying. She rudely stated that she was going to call the police on us.
Well, maybe another hour later from her phone call she decided to come up here with the products purchased and her husband wallet. She threw her husband wallet at me and insisted me to take a look at how much money he had left in his wallet. She asked me to ring up all the products and give her a receipt. Which I did and it came out to about $35.
Now, to prove that she is obviously the one lying. First of all, she said that her husband spent twenty something dollars. That wasn't true. Then she stated he purchased chewing tobacco products, that was false. It was all rolling tobacco products.
When I spoke of the truth to her, she started to bang on our credit machine and asked if I could pull up the original receipt of her husband items. There was no way I could do that because the machine she was banging on was the credit machine. After I told her that she began to bang on our register machine. The register we have does not have that option either. She started speaking that Smoke city workers was liars and/or thieves.
She came in as if we would remember who she was because she wasn't even the one that had come in to purchase the items. Maybe if her husband would of have came in and talk to us, things might have been different. But we had no idea who she was and there are a tons of other customers that came in.
She made a huge scene in front of many other customers. She backed up our line. When she left, our customers that patiently waited for her to leave, told us that she was so wrong for what had happened. The told us that they have never had any problems with us. They also stated that she was at fault because they should have counted there change upon leaving.
That's a pretty brief explanation of what happened.