Parental Controls not working, potential DNS issue

[jdmccarty515]

Orbi RBR50v2

Firmware V2.7.4.24

ISP: Comcast Xfinity

I've recently resubscribed to parental controls and armor however they do not appear to be working (i.e. device specified with content filtering is allowing browsing to objectionable content).  It appears the DNS is set to Xfinity's DNS service (75.75.75.75, 75.75.76.76) and the ability to change is disabled.  My understanding is that the parental controls should be using it's own preferred DNS service.  Trying to solve this before demanding a refund on services that don't operate correctly.  Apparently, despite having just subscribed to these services I am not permitted to open a case with support.

Any pointers would be appreciated.

[FURRYe38]

Can you not change the RBRs DNS configuration using a PC and web browser under Advanced tab/Internet Setup? 

How was the system initially setup? 

What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too?

Your behind on FW as well:

https://community.netgear.com/t5/Orbi-Wi-Fi-5-AC-and-Orbi-with/New-RBR50-RBS50-Firmware-Version-2-7-...