Ashworth University I have never attended this school, but I am getting threathing mal and calls saying I owe them money Norcross Georgia

I have a Bachlors degree in Psychology. However, in the past two years I have been recieving threatening calls and mail from Ashworth College saying I owe them money. They even took out over a 1000.00 dollars out of my income tax last year. I have never attended this school and to be honest I have never even herd of them until last year. I have made numerous of calls to try and resolve the matter but I always get the run around and continuous bills. Does anyone have any suggestions as to what I can do to stop this and possibly get my money back.