Would this be defamation of character? And if so what would I be able to do about this?

A manager at another store called to get a reference for me my boss told her that I have an attendance problem when I had only been late for 3rd shift which is 2 am to 9 am
a few times and I always stay to make up my hours. And come in when called if someone is sick or can't work ... Infact my last few checks I have gotten over time because I worked alot of hours ... Being tardy is not having an attendance problem ... Two totally different things and I have missed out on alot of job opportunities because she keeps lying to these employers about me. She is trying to keep me there because I am a hard worker and I pick up her slack, since I can run circles round her and can do her job better than she can I intemodate her and she will not promote me at the store I work at now and has blocked me from being promoted at other stores within the company ... When I am more than qualified for the assistant manager position.