Sorry to hear that. If you guys were compliant with what was required of you (eg clean house, neat garden etc), you shouldn't get too upset. As much as I know it's upsetting.
Our own landlady was the rudest b̶i̶t̶c̶h̶ person ever I wanted to s̶l̶a̶p̶ ̶h̶e̶r̶ walk away but I keep telling myself - I pay rent, I keep clean, now back off. Now I will only speak to her husband.
Continue to be the perfect tenant. I personally won't rock the boat as long as I haven't got the next place lined up. I have learnt, many times even when such a complaint is made, nothing much is done. I might tell it to the property manager in his face "lose that attitude. no need to talk like that." Standing up for yourself works well in this country.