Comcast Cable Comcast is charging me for Service AFTER I have been disconnected Denver, Colorado

My bill for Comcast on June 13 was $227.11.  On June 29 Comcast issued a soft disconnect for my service. (June was my first bill after our year promo of a $119 bundle and it went up way to much for us to keep.)  We had dish network hooked up on 7/4. A Comcast service tech came to pick up the equipment on 7/14.  All equipment was returned.   I now am receiving bills from a collection agency saying I owe $465.53 to Comcast.  I called Comcast today and they said they still charge for service until the tech comes out to do a physical disconnect.  I asked how that can be when I could not get a picture.  Robert (Comcast manager) explained I could hook the tv directly up to the wall.  I asked if I could get digital service (which is the package on my account) and he said no, just basic service.... OK-- so how can i be CHARGED for digital service if I can't get it? I told him I could understand if I was charged basic service (even though I didn't know that was possible to get ANY picture).  He said that because I still had the digital equipment, I still have to be charged digital programming!  HOW??? Can someone please explain how this is RIGHT and how I am NOT being ripped off???