Received a call. No message was left and I didn't answer.

It is actually a number for internet VOIP phone service that serve a lot of locales.

VOIP phone is different from the conventional phone service, check it out.

we are a medical tourism company and we are getting frequent from this number and when we call back,there is no response.

The caller is using a VoIP provider and is not configuring their caller ID, so the provider's default caller ID # is used instead. I know the provider but I feel that is irrelevant. They are a great company and it's the spamming customer's fault, not the  provider's fault

I would like to know who the provider is.  I work for a call center and am paid .15 a min for talk/order time.  Someone from this number is continually calling and making prank phone calls, which does cut into my time and $!  If you would provide it, I would like to contact them to see if there is something that they can do about tracking this person who is making these childish calls.  Thank you!