Financial Issues Still the Biggest Reason for a Clearance Denial

Hello, I have my appointment for Polygraph and medical exam in a few weeks, but a week ago I found out that I was victim of scam/fraud (criminals deposited an authorized check into my checking account). I reported the incident to the FBI.
Two days ago, i found out the bank reported the crime to the Early Warning Services and now I can’t open any account with any financial institution. I tried to talk to the bank in order to make myself responsible for the overdraft and make payment arrangements but the bank don’t want to talk to me. I’m devastated, I never did any illegal action in my entire life. What else do I need to do? Will I be able to fix my credit?
I talked to the institution that requires the security clearance and I explained that I was a victim of fraud. The person whom I talked to on the phone told me to go to my appointments (polygraph and medical exams) because they will run their own investigation. Do I need to hire a lawyer?
Please, I need your advice.