Switched Provider's Dead VPN Netgear CG3000DCR

Switched from a previous provider for the speed comcast could offer. I have tried just about everything in my power on this modem to let our VPN work as it did before. I disabled DHCP assigned the gateway that I wanted along with the subnet mask. I have done this for our previous provider and it works fine. Not understanding what I am missing or what I need to do to make this work. I have been through the forums, but have seen about 5 different fixes. We have a Cisco Router that handles our VPN/DHCP. My question is, Do I need to set this modem to "True Bridge Mode" or do I need to get a static IP. I have called a couple times, the tech's keep telling me its on my end. That I should contact my router company and that the modem is fine. I find that hard to believe when I can plug in my DSL line (That's still active while I'm on my 30 day trial) with the same setting's I am assigning this one. Yet, I get different results. Any light shed on this would be terrific. Thank you.