Connection Pro with internal static IP addressed PC and CC Machine

I purchased an Internet/Phone package with Connection Pro for backup.  I have a retail store and I need my point of sale PC (cloud based POS) and CC machine to have redundant internet so that I can continue to do business should my main internet connection go down.  I was sold this package as it was labeled to be the perfect solution for this exact scenario.  I was very happy as the price was good and it checked the boxes of what I needed.

Now the problem is that both my POS PC and my CC machine have to have static internal IP addresses.  I didn't think this would be an issue as every router has a DHCP range and a non-DHCP range (available for static IPs).  But, I've come to find that the connection pro device apparently only works with giving out DHCP addresses and you cannot use static IP addresses.  WHAT???  I think the network that the connection pro device uses is 192.168.165.X/24.  I've contacted support multiple times to find out which addresses are in the DCHP scope and which ones aren't so I can use those for static IPs.  Nobody can tell me.  Nobody can explain any of the settings of the connection pro device and just say that it's not configurable.

Not being able to use static IP addresses blows up the whole solution and reason I bought this package.  I have opened two cases with support and I get nowhere as they really don't seem to understand either what I'm asking or they don't know how the connection pro device works.  They keep getting internal IP addresses confused with external IP addresses or they suggest I setup the connection pro as a pass-thru so that all IP management goes through the main Comcast router.  That works great until an outage, and then my critical static IP endpoints won't work when  the connection pro device takes over and uses a different IP network to function.

Can anyone here help with this?  Is it possible to use static IPs on devices connected to the connection pro device?  Is there a range of IPs on the connection pro device that aren't part of the DCHP scope?  I am really hoping to get some better insight on here than what I've gotten from calling in.