Can previous tenant sue me for contacting his employer regarding debt?

My previous tenant asked to do an early lease termination so that they can move out of state due to a job change. Our relationship had been tense because for the 3 years he was living in the property, he had been late 90% of the time. So by the time he left, he didn't even tell me where they were moving to. I signed off on his early lease termination trusting that he has paid all his utility bills including water bill. But he didn't and left me with a $395 water bill. After two months attempting to contact him and getting him to respond in no veil, and not knowing any other way to get him respond, I contacted his employer. I apologized for having to contact his supervisor but I really had no choice because I trusted him and he just wouldn't pay! He apparently knows or learned the legal stuff and sent me an email asking me to stop contacting his employer. I had no idea until I got his next email and after I Googled why he sent that email. I simply replied and told him that I don't enjoy