Voice VLAN only allowing one way voice

Hi all

I having an issue with my Netgear switches and Mitel phones. We are using Mitel cloud for our MiVB & MiCollab.

We have 6 GS728TXP's in each office that connect back to a XSM4324CS core switch. All are on the latest software release. Data is set to VLAN 30 & VOIP to VLAN 40. I have setup Auto-VoIP according to the below article.

https://drive.google.com/file/d/0B4PuVEYxkQ5od0REZVNSVlhLX2lQMTdOb283S3BiYWFxRkdr/view?resourcekey=0-teDMN81yabPbzpoKGltH5g 

When I connect a phone (Mitel 5330 IP) I can see it going to the correct VLAN, (40), for DHCP.

Once the phone has booted I am able to login. When I make a call (internal or external) the call will connect and I can hear the called party, but they can't hear me. I have tried several different phones in different switches to rule out and broken devices. On a slightly strange note, I have had a couple of phones work. When I have tried them in another port or switch they have not worked and then, when plugged back into the original port they are not working either. I've tried not using Auto-VoIP but stil the same result.

We are currently using the Mitel softphone app on PC's so I know that the voice is working.

I'm at the stage of pulling my hair out as I can't seem to figure out what else to try. Any suggestions would be gratefully received.

Thanks.

Richard