COX blocking a legit internet site? Need help

I have a 100% legit website I have been using for years.  I also have some Raspberry Pi computers that also connect to this server to perfrom

tasks.

A few days ago I could not get access to the site. I would get a "Time out error"  on my PCs and my Raspberry Pi devices would not connect.

I bypassed my modem (ASUS RT-N66U) and went direct to the modem.  I could not get to the site with my PC.  The raspberry pi devices rely on WiFi.

  I would assume at this point the Router is the problem.  After sever reboots of the router, factory resets, clearing the NVRAM of the router, with the router in

line I could not get to this website.   I could get to the website bypassing the router  and on my cell phone when using cellphone tower.

I decided to swap my routers.  I have several of these RT-N66U routers.  I did a factory reset on the 2nd router and installed it.

Everything was working.  I assumed the problem was fixed.  After about 6 hours the 2nd router started the same problem, cannot

access to the website and my raspberry pi computers also no longer could connect.   The second router and when my computer was

connected directly to the modem both gave me new Public IP addresses.  After having COX reboot my modem twice, spending

time on the phone with a tech wanting to sell me tech service I need to talk to a higher level COX tech who can at least tell me

if they are blocking certain websites/servers and is it based on the mac address of the device connected to the modem.

I have temporarily resolved the problem by changing my routers mac address to one of my computer laptops with the last

digit of the mac address changed.   This has been working well for almost 12 hours.   This also tells me the 1st router is good

and I could have changed its mac and most likely be working like I am now.   

How can I get access to a higher tier COX tech to review this and find out if COX is blocking certain websites?

thanks,

Ken