Inform your employer what is going on..this has worked for me because this same thing has happened before to me in the past it will annoying at first because they will keep trying to call your place of business so you will be afraid or be embarrassed because they are calling your job don't give in don't send them anything because if you do they will still continue to say you owe more or another scam company will call you. They are scammers based out of India so it is hard to track them ,when they see they can't anything from you they will eventually stop