Forgot to transfer utilities on moveout; am I liable?

[Joseph La Monte]

BPers, several years ago my lease ended and I moved out of my apartment in North Carolina.  However, when I left I forgot to transfer the utilities back to the landlord.  The next tenant moved in, never transferred the utility account to him/herself, and never paid the utility bills.  The bills accumulated unpaid and I did not know about this until I checked my credit score last week.  Duke Energy sold the unpaid amount to a collections agency, which is after me to pay those bills and wreaking havoc on my credit. 

Am I liable to pay for unpaid utility bills in the property if I was not under lease at the time?  It doesn't seem to make sense that I would be, but can't find any legal precedent to support me. 

Thank you for the help.  I hope that I posted this in the correct forum. 

Joseph