Missed phone calls mysteriously forwarded to cell phone

Back in June, we had forwarded our phone calls to my cell phone. This was cancelled in July. And when looking at my Phone Information, this cell phone number is not listed anywhere and the only forwarding turned on is for Cox Voice Mail. BUT, for several months now, whenever a call to my home phone is NOT answered, I receive a call on my cell phone showing my home phone number as the caller ID, and when answered, it says "you have a voice mail from (our home phone number)" and just repeats this message over and over. And if I check voice mail, there is no message there. I have contacted COX support several times about this issue and they cannot figure it out. They insist that the cell number we claim is being called, is no where on their computers data base. Cox acts like the situation is impossible. BUT, it surely is happening every single time a home phone call is missed. Can anyone out there make any sense out of this and suggest how we may stop the Cox phone system from calling my cell phone when an incoming call is missed????? Thank you.