What can i do?

I got in some trouble in 2016 and got charged in court in 2017. I got the book throwed at me due to my manager at work because he is a ex-police officer for the county I got arrested in. Now he is interfering with my probation. he called my probation officer and told him I was riding around smoking weed so I got called in for a random drug test and managed to fail it out of the blue. I been on probation for almost a year and haven't failed not one drug test until today and my probation officer told me who called him. So how do I handle this problem?