What should I do after being falsely accused of stealing at a store?

I brought a drink in. I usually have no problems. They don't sell the drink there.

He slammed my stuff on the counter. I went out to the car and got the receipt.

He tried to say something I wore I stole from there. but I wear it all the time and I have had it for years.

It's the same security guard that used to harass me at the this high end grocery store.

The girls who work there are really nice. I guess I can't shop there.

Updates
4 mo
I wonder if my ex said something. Him and his mom live to accuse me of stealing.
What should I do after being falsely accused of stealing at a store?
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