Static IP

I was told by a Cox rep a few weeks ago that I was assigned a STATIC IP.  it appears I have DHCP.  I would appreciate a static and am willing to pay extra.  I have a home office and a satellite office and a good majority of the time I leave a file or two on my home PC and have to RDC in.  this becomes cumbersome when cox rolls my IP.  I have other ISPs that are willing to give me a static.  I don't understand why in this day in age a residential account cant have a static IP.  Please don't respond to this with some third party app like team viewer or some DDNS. NOT INTERESTED.  I was told by cox I have a static (if you guys record the calls like you say you will hear it) I pay for my services and I believe there is no reason to be denied a static IP.  I would like to know why I was told I was assigned one and also what reason is behind not giving a customer who requests it, a static IP.