can only access some sites IPV4 IVP6

I could not seem to post a private message, so I am posting this with your contacts.

A technician was at our home last night .  We are not able to access the internet via any browser on any of our devices (dell desktop, iPad, iPhone and 2 HP laptops).  He was aware of this megathread and and asked me to send you this post with our CMAC address from the modem: CMAC: F88B372B0B68 

Been through 3 modems, 4 phone call and 2 technicians.  So, happy the one last night knew waht he was doing and was current on this problem!  

Please let me know any help you can provide. Thank you!