Unusual EYFS situation, possible discrimination

Hi there,

If I had a parent pull their child out of the setting (effective immediately) because they didn't agree with a rule we have put into place (late fee for invoices not paid in time) and family members are now spreading lies and general badmouthing about the setting. Would I be allowed to not allow them to come back to the setting? Or would this be classed as discrimination? Literally a day after pulling their child out, they have received their funding and will be ringing me next week to ask to have their space back I hear. Just looking for some ideas on how to navigate the situation!