Intermittent Outages which last for hours to days

Like some of the recent posts, I have also had intermittent outages over the last 2 months which last a few hours, and over the last few weeks, have lasted 1-2 days. 

I have scheduled tech visits 2 different times, only to have service restored literally the night before the tech visit.

I have switched out my modem at the Cox store and am still having the same issue.