I get why you are upset @Kidsdontknowwhatswrongwithmum, anyone would be.
You're in portugal? I'm surprised tbh, I speak portuguese having lived in Brazil when I was a lot younger (sorry, not sorry @SerendipityJane) and IME i've only ever found people to be kind and resepctful in portugal. Brazil is another matter, but that's manageable with afew well chosen expletives :D
I think you can be reassured knowing that the supermarket HAVE acted on your complaint and this guy will have learned a serious lesson.
I have had similar in London with a guy on a tube from Angola who was bitching about the entire carriage on the way. He thought nobody understood him, but I did.
Eventually it came to my turn apparently and I folded my copy of Metro and said to him (in is own language) to be careful and to remember that portuguese speakers come from all over the world. He actually blushed and gaped :D
If I were you - not that I would ever expect anything like this to happen again - I'd have a stock phrase up my sleeve to tell him that he's a dick and to fuck off. It'll make you feel less vulnerable.
Please don't let ht eidiotic behaviour of one person affect you like this, others at that supermarket backed you up by telling the management who it was, and that should be sufficient for you to know that what he did was wrong and it won't happen again.
Don't let that dickhead ruin your access to the supermarket - go in there with your head held high. Chances are the staff won't recognise you as the person he said it to anyway.
Coragem!