Furqan,
This is not allowed by PTCL at the moment. Major companies obtain LD licenses, but that too is for outbound dialing. Inbound calling over VoIP (termed as termination) is strictly forbidden.
Shayan,
Quintums are good, cheap gateways for startup call centers. They may not be the “best” in the market, but certainly are worth their money’s worth.
Regards
– Harris