One way voice when changing ISP's

[immobilier.frazer]

I have been a happy freephoneline customer for 2 1/2 years now with very little to complain about. Just recently we switched internet provides to a Bell Mobility plan and now I have this problem. Whether I call out or someone else calls in they can hear me, but I can't hear them.

Here are my settings:
Registrar Address:voip.freephoneline.ca
Registrar Port: 5060
SIP Proxy: voip.freephoneline.ca
SIP Proxy Port : 5060
Outbound Proxy: voip.freephoneline.ca
Outbound Proxy Port: 5060
Register via Outbound Proxy (yes)

I have tried with voip2.freephoneline.ca and voip3.freephoneline.ca with the same results. I have also tried voip4.freephoneline.ca with port 6060 (didn't work at all).

a port scan gives these results:
PORT STATE SERVICE
5050/udp open|filtered mmcc
5060/udp open|filtered sip
6060/udp closed unknown

Does anyone have any ideas?