someone called me from this number asking for someone from pakistan. Very strange?

I have recevied this call usually about 3 time a week for the past two months and there is no one on the other end. Everytime I dial it back there is always a busy signal. I use to be with Vonage but this problem didn't start until after I switched to our local phone company service.

Have had this number call 3 times, no one ever answers, I've tried waiting as much as a minute.

This is a Vonage gateway, it doesn't dial in to anyone.  It will show up on the caller id from anyone who may be using Vonage VOIP for their telephone service.