Can my ex landlord go to my job and talk to my manager about the money i owe him?

I didn't even had a contract with my ex lanlord, when he asked me to leave the apartment i agreed and found a new one, well i wanted to pay him everything i had left to own him, but since i don't have a job now its really hard to pay him the 300 of everything i owed him. she has been going to my job making a scene and causing me problems with my manager. and now she even went on my day off and talk to him about the money I owe her. can some one help me with i can do and what rights do i have. i think this is harrasment because she keeps calling me, sending me text going to my job and causing me problems..... well she even said that she is going to sue me and i need to pay their attorirney plus the 300 that i owe and another 1000 dollars more? is this posible? please i need help with this.