Static on Panasonic phone system via Ooma

On or about 1 March, my five year old four phone Panasonic system hooked up via Ooma started and continues to have static when picked up or when using the speaker phone button.

I have just bought a new Panasonic phone system but it has the same results.  I have an Arris Surfboard modem SBG7400AC2 on your list of acceptable equipment.  My current Internet plan allows for 2000 mbps 

download and 250 mbps upload.  I've been told by the Ooma folks that the "ping" adjustment has to do with latency and could affect clarity to include inclusion of static.  Advise if I can get help on this matter or if something was done internally via Xfinity on or about 1 March to facilitate the issue.  I have done all recommended solutions about moving equipment away from walls, other electronic/electrical stuff.  Advise.