Warden defaming and letting me work

I was working with a university in Chandigarh as a chief hostel warden.there is a man he was previously handling this position. He is very close to management .after I jointed many ways he harrased me and never allowed me to work.many time I complaint against him to the management but my words never listened .I tried to leave this university many time but mangment never allowed me to leave.then finally I left and joint another university after I left opently I wrote a open letter to the management said what ever problems I faced from this man..but through the university he sent a letter to my new university against me . for this I forced to resign from my new job.now I again got a offer from one university but I am afraid he will again spoil my job.so what I should do .how I stop him .he is very clever guy .he is fooling a organisation most workers are against him...please advise..