Trying to figure out what tv boxes are still outstanding.

Basically, moving to Oaklahoma for a few months while home is being renovated.  Turned off the TV services and left the internet operational while I'm gone so I can access the security system through my phone and the contractors have access to internet for music as well.  On my bill, it says that I was paying for 1 primary box and 4 sub-boxes rental fees.  So I turned them in.  But according to their records, they still have 2 boxes outstanding even though they are not showing as a rental charge on the bill.  I know that the panoramic wifi modem is still being rented, but they tell me there is 2 more items.  When I called to check on if they were primary boxes or mini boxes, the people on the phone said they cannot tell as they only see the serial numbers. 

So my question is how can I tell what items are outstanding and of what types?  Also, why wasn't I being charged for them if they were Cox property?  I only had 1+4 as long as I can remember so it's just confusing to me.