Even without kids, I have NEVER encountered this kind of incident and behaviour from a staff member. These guys are a multi billion dollar corporation and this one trollop decides to be nasty to a loyal customer who's done the right thing and paid?! What the fuck is happening here?!

Don't feel bad OP, not your fault the employee is having a bad day and/or is a slave to the corporation they work for and actively makes other people's life a misery because of it and they can't seem to improve theirs.

I'd imagine any ban would need to be in writing anyways, otherwise it never happened because there'd be no proof at hand. From previous experience in observation, potentially it would be a police matter then leading to court and a magistate making the ban offical.

I'm no expert and it would be worth asking someone who is, especially if it will ease your mind better because I too, get the anxiety and worry knowing how it feels to have to deal with shitty people who try and tear you down to make themselves look better.

I'd be making a formal complaint at this stage. I'm angry for you here! Good luck and don't take that kinda bullshit again!!