Buying Used Cable Modem

I am considering buying a cox supported modem, used.  The seller has told me "all devices are considered 'technically destroyed' when they are not on an active account and service provider should reinstate them accordingly"

If Cox Representative visits this site .. can you confirm that I can purchase this modem and get it to work on my Cox account?  Or has anyone else on this forum purchased a used modem?

Thanks in advance