NTELOS WIRELESS charging me for a phone I no longer have and after I completed contract because phone can not be used in Florida Waynesboro, Virginia

RE:  Acct # 158635879   Tel # 757-718-7472

When I moved from Virginia in September, 2009; I called Ntelos and asked if Florida had Ntelos.  The girl I spoke to said no.  I asked what I was to do because my contract did not end until December 16, 2009.  She stated that I had to finish my contract but she would reduce my payments to $9.99 to the end of my contract.  She was going to give some minutes until September 12, 2009.  I left Virginia on September 10, 2009 and did not use the phone once I left the state.  No one said that I had to do anything further.

This is now March 5, 2010 and today I received a bill from Ntelos stating I owed them $59.45 since December 16, 2009.  I called  the 1-877-468-3567  number and was sent to someone, I believe her name is Mary.  I stated this was the first bill I had received here and my contract ended December 16, 2009.  She stated that I should have received bills in Janurary and February 2010.  She also stated that I had to call in December, 2009 and cancel.  I replied that I was made to understand in September that when my contract ended that would be it.  She stated that that was not true and that she would take away the March 2010 payment but I still had to pay $36.85. 

Now here is a phone that I couldn't use but still I honored my contract.  My contract was up December 16, 2009 but they continued to charge me.

I need to know what my legal stand is.  I honored my contract until the end.  I do not want to ever do business with this company again.  I will also inform anyone I know in Virginia that is using Ntelos what they have done to me.  How can a company continue a contract that has ended?  Mary stated that I could not cancel my contract that far in advance.  The girl I spoke to on the phone in September, 2009 did not state that I had to do anything else but pay until the end of my contract.