LB2120 incompatible with XR700 and CM700?

[chris12]

I have an XR700 router connected to an LB2120 LTE modem which connects to a CM700 cable modem.  Everything worked fine until I added the LTE modem.

I have the LTE modem configured in "Bridge" mode, have alerts enabled and have set the proper APN for my simcard.  Everything else in the LTE modem is set as the defaults.  The CM700 is set to its factory defaults.  The XR700 has the internet connection set to the defaults (DHCP, no login)

Since owning the device in Decmeber there have been several occasions where my CM700 is online, my LTE modem appears to be working but my XR700 is not getting a WAN IP address.  The solution seems to be to reboot the LTE modem (reboting just the XR700 does not fix it).

The easiest way to reproduce this issue:

1.  Set up a network as described with the XR700 connected to the LB2120 then the CM700.

2.  Turn everything on and confirm everything is working.

3.  Browse to the cable modem (192.168.100.1) and reboot it.

4.  Note that the WAN IP address on the XR700 brieflly goes to 0.0.0.0 followed by 192.168.100.20 followed by 0.0.0.0.

5.  Leave it for a few days and note that the XR700 is still not connected to the internet despite the cable modem being connected just fine.

Once the network gets into this state the solution seems to be to reboot the LTE modem.

[chris12]

I'm getting no luck with the support department on this.

I spent an hour on the phone on Tuesday and was eventaully told I needed to wait for a call back from the higher up support which would be within 24-48 hrs.

No on called, so I called back on Thursday.  I was told the first agent made a mistake.  Was told this is a common problem and the higher up team would contact me in 24-48hrs.

On Friday I receive an email asking me if it is still a problem then asking me to call back.  I've called back and was asked the same basic diagnostic support questions again.

I've now had three hours of phonecalls on this, some promised callbacks but none actually provided, and seem no closer to resolving.

Does anyone have advice here?  It is slightly outside of the return window but amazon are prepared to accept a return but will only refund 80% of the value.  Should I just return it and accept that I've lost about $35 by buying a defective product; or chargeback the full amount on my credit card?  Doesn't seem like netgear are prepared to help.