policy violation

Hello, I was working with one job provider consultancy and on the payroll of this consultancy I was working at client location. Now I have left that firm due to very bad treatment and lots of politics. I have left the firm on 10th Jan, 2015. Before two days, I got a call from them saying that there are some bad reviews posted on glassdoor. Glassdoor is platform where everybody can provide reviews about various companies they have worked for. They are threatening me to file legal case against me as it is violation of policy of the company to post reviews while on employment of the company. They are telling me that they have proof that it is posted by my id. Now the thing is I have not posted it from my account that is gmail ID. I have asked the lawyer who called me that tell me the id from which it is being posted but he has not given any details. He is just insisting to remove the reviews. He called twice and threatened as I mentioned above. I dont know what to do. Please help. Without doing anything, I am being tortured.