VIVA offers IP based Converged Communications Solutions. You may contact VIVA for SIP Trunking, IP PBX & PSTN integration, MS OCS & IP PBX integration, Managed VoIP and ''''Secure'''' VoIP.
Check the rate list:
http://hackwere.com/voip/
User: rate*hackwere
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Call me for exchange rates because of up and down