TP Link TL WR641G/642G Router HELP!!!!

My setup is as follows:
Modem Motorola SB5120
Router TP Link TL WR641G/642G
Voipo Grandstream Device

I have internet and I can dial out and talk to people just fine.

However when people call me I cannot hear them and they cannot hear me (dead air)?
Occasionally I can hear them say something and I try and respond but the other end just hears dead air?
I have dialed my number from my cell phone and it rings 4 times then goes to busy signal?

I keep reading in the forums about this port forwarding. This is enabled in my router and as far as I can tell the Grandstream device is being forwarded (see below).

Current UPnP Settings List
ID App Description External Port Protocol Internal Port IP Address Status
1 Teredo 51941 UDP 51941 192.168.1.101 Enabled
2 Teredo 62924 UDP 62924 192.168.1.102 Enabled

I have switched from Vonage to VOIPo and never had any of these issues with the Vonage device or setup.
I still have the Vonage device and am wondering if I should hook it back up in place of the Grandstream device?

I also have two separate lines plugged into the device (one goes to my DISH Network caller ID the other to my Dect Cordless Phone).

I would like to make this work because I would like to switch my company over but I'm having this much problem then I may have to reconsider.

I am sure the fix is an easy one and I am just overlooking something.

Thank you in advance.

Please contact our support team for assistance.

Right now support is basically dead with only 3 tickets open in our general queue and agents fighting over calls so you should be able to get help pretty quickly.