Who should I contact regarding threatening calls from someone claiming that I owe money that I do not?

This person has identified himself as Officer Rogers and will not give me anymore information. He makes random calls to my work place, calling several ties demanding that I give him my banking information to pay off this debt. He states he''s callng from easycash and his representative wants nothing to do with me. He has spoken to co-workers, my manager, and not he wants to contact human resources. I have told him it is a fradulent call and stop harassing me at work but he is very persistant and will not stop calling. Somehow, he has obtained my social security number. I have contacted Baltimore City non-emergency line and the State''s Attorney''s office Please advise me on what I should do when he calls again, because hanging up on him is not working.