AFNI Debt Collection, ANFI, Bloomingtom IL

I closed my DirecTV account in April.  In May, I started receiving calls from ANFI stating that I owed $60.23 to DirecTV.  The caller asked for immediate payment over the phone.   I refused and gathered as much information from the caller as I could.  After being on hold, the caller gave me an account number.  I called DirecTV who did not have a record of that account. 

 There was an account for my name under a different number and I was told the account was up to date and no past dues.    Again, I recieved calls from ANFI demanding I pay them money or they would ruin my credit.  I disputed the debt and asked for a mailed invoice.  I was told that they don't do that.  They are only to collect payment now.  Again I refused, disputed the debt, and asked for a mailing of information.  I have yet to receive anything.