Call forwarding and Betamax

[mian]

Ok here is my input so far.

I am using DIDWW and TPAD nos for incoming calls
TPAD is registered

VoipDiscount for outbound to USA and CANADA nos.

Tried us. eu. au.

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in simple terms

LandLine -> DID -> Voxalot -> VoipDiscount -> mobile (Canada)

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50% everything works
I can hear phone ringing on LandLine and mobile both ... and have two way sound

50% I can hear only two rings on Landline - Mobile keeps on ringing - on pick up I CANNOT hear anything on my mobile but on my landline I can hear what is being said on Mobile (One way)

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Interesting part

If I bring in Grandcentral i.e.

Landline-> DID -> Voxalot -> Voipdiscount -> Grandcentral USA No-> Canada Mobile

Works 100% no problem except for bit down graded voice quality


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I have registered my WIP300 with VoxaLot but it is mostly turned off and not registered at the time I make these test calls


Any input