Netgear CM500 2 downstream channels not locked - Blinking Green light

I upgraded my modem to CM500 and saw blinking green light on downstream. Looking at modem logs, out of 16 channels, only 14 are locked. Also i have seen by the end of the day my modem speed goes down to 3 Mbps and eventually resets (I should have 150 Mbps down)

I upgraded my modem, to no luck. Also my coax cable is nicely fitting and I dont have a splitter.

I do not think I get all the download speed I am supposed to get.

Any ideas on how to approach with this problem?

Do I need to call Cox technician for diagnostics? How much do they charge?

Thanks