Product: Checking or savings account

On XX/XX/18, I was contacted by someone from the XXXX XXXX XXXX, who stated that I was owed {$520.00} credit from a computer company that went out of business for services that I purchased. When the refund would not got back on my XXXX card, they asked me for my bank. I told them USAA, but my account was credited {$2500.00} instead of {$520.00}. I was sent an email with the USAA logo stating that I had to pay the difference of {$2000.00} back to them in gift cards from XXXX. I went to XXXX, purchased gift cards and withdrew {$2000.00} from my USAA account. I called USAA that night to ask them to verify where the funds originated from and they could not tell me. I told them that I felt that I was a victim of a scam because the XXXX XXXX people had used/accessed my computer and I could not get back on my computer for an hour ( which I felt was suspicious ). I called USAA again next day and they transferred me to a fraud division to file a complaint. They still could not tell me where the funds had originated. I decided to close my account beause of 1 ) the way the representative handled my complaint and 2 )  XXXX called me and told me that someone had tried to make a purchase at XXXX and XXXX XXXX on my card also on XX/XX/18 for {$400.00} and {$200.00} respectively. This confirmed that I was a victim of a computer scam. I tried to close my checking account on XX/XX/18 but had to wait 24 hours till XX/XX/18. 
I received a letter from USAA on XX/XX/18 telling me that there was no fraud on my account. I also received a letter two days after telling me that my account was reopned and that I had to pay {$2500.00} in 41 days or it would be reported to credit agencies. 

1 ) Why was my account reopened after I closed it? 
2 ) Why can't USAA tell me the origination of the first credit of {$2500.00}? 
3 ) Where did the debit of {$2500.00} originate? 
4 ) Why was it so easy for the scammers to access USAA account without me giving them checking account numbers or anything, but the name of the bank. 

I called a representative again a couple days ago, still no one can tell me where the credit originated from. As a banking institution, anyone can put money in and take money out of someone's account with no identification name or source. Don't banks monitor deposits and withdrawals. They want to hold me accountable when they can't hold themselves accountable. It was a scam obviously. XXXX was professional enough to investiagte and credit back my acoount, but USAA wants me to be victimized again. I want them held accountable for the credit to the account originally when I did not even give my checking account number to the alleged XXXX XXXX XXXX scammers. Aren't there laws to protect customers from scams using the banks? 

So now I will be scammed twice. 1 ) By the scammers for {$2000.00} and 2 ) by the bank for {$2500.00}. I have a thirty year credit history with no late payments ( this can be verified ) on it but now this incident will tarnish my credit history. I will not be victimized again. I also reported this to the Federal Trade Commission Consumer Response Center for the computer fraud and I have a reference number.