Connection Issues - Same IP Address

Hello Everyone

My family and I are struggling with interrupted connection issues.  I recently upgraded my internet speed with my internet service speed and bought this modem/router used on amazon.com (I tried to buy it new, but could not find that option).  This is one of the few devices that is approved by my internet service provider for their service in our area (Now Spectrum, but formerly Time Warner Cable).  I previously bought a new Netgear router/modem (AC1600) that was on the list of Spectrum-approved modem/routers.  I connected it and it would not work.  I contacted Spectrum and they said I needed to purchase a modem/router on the Time Warner Cable-approved list.   

We are on the Windows 10 OS.  On some devices, connection is lost for any where from 1-10 minutes, and then it gets re-established on its own (without me changing any settings, rebooting the modem/router, etc.).  On other devices, we get the following error message:

"Windows has detected an IP address conflict.  Another computer on this network has the same IP address as this computer.  Contact your network administrator for help resolving this issue.  More details are available in the Windows System Event log".

I've contacted Spectrum and they've said everything looks good on their end regarding the modem/router connection.  They sent a "corrective signal" and then suggested I reboot the modem.  I've done this a few times and it seems to make things better for a day or two, but then connections deteriorate again.   I've also checked out the modem/router's admin site/settings and I don't see anything that looks out of place.  Can anyone out there offer some suggestions as to how I can fix this issue for my family?  Thanks in advance for any suggestions you can offer.

Regards,

Jon