If the sytem of my hired account was hacked and affected my files, he would not assist me with this problem, is there anything I can do?

I paid a tax accountant to file my taxes. I was later informed that his system had been hacked. I found out that a fraudulent return had been filed in my name.The IRS said I needed to go thru my accountant and to have him file another return. After numerous calls to his office the receptionist finally put him on the line and he was immediately defensive and stated he did nothing wrong. Needless to say the conversation became heated on my part as well as his. I now get a letter from the IRS stating that he withdrew his Power of Attorney and would not assist with this problem.