Having outages that begin around 11:00pm EST?

During the week of 15 to 22 April, I got complete outages that begin somewhere between 11:00 and 11:30PM EST - always during this window.  These outages can be intermittent or complete disconnects from one hour to several hours.  Cox technical support claims that are no known outages in my area. I could explain everything I've done on my end (e.g., direct connect, new modem, tests, etc.), but the problem is definitely with Cox.  Whatever maintenance or upgrades they are doing, they are not telling the Tech Support personnel at their tech support call center.  So frustrating when they insinuate it's your (our / my) end and the time this occurs is always the same, which clearly points to Cox doing something.  I've spent hours checking, grooming, replacing my whole network. So at this point I feel insulted.

They suggested a tech visit, so I said OK just to prove it's not my end.  Their window; 8:00 to 10:00am.  I got a call at 9:45am saying the tech was running late and should be there before 10:30am.  At 10:45am I called Cox to cancel.  They said they're sending another tech who should be here any moment.  I still said I was canceling.  At 10:50am, a tech showed up.  I politely explained that I cancelled the appointment, and all I wanted anyway was to prove it wasn't my end.  Additionally, there could be a charge for the visit. For a support visit that they picked the time for, with a tech showing up 50 minutes past their 2-hour window, and that they would possibly charge me for this visit, I feel insulted a second time.