Its probably the canadian pharmacy, which his NOT in Canada but in India. They sell phone numbers and apparently use magic jacks so the calls look like they are coming from the US, when none of the callers sound American, more like Indians from India. The phone numbers change often with new people on the other end, its seldom the same people making the calls more than two times. I have been receiving these calls for about 9 years and at all hours. A real Canadian Pharmacy has expressed dislike for what they jerks are doing and making folks think they are dealing with folks in Canada. When they call, you can claim they have the wrong number, or you can order 5,000 viagras, 10,000 valium, 5,000 demerols, etc. They get excited for getting such a big order, some they will want a scrpit, so just tell them its in the mail along with the check to pay for it all. They will keep calling, just keep jacking with them.
A few hours after telling another spam # not to call I receive a call from here. The other reporter may be on to something as far as them selling numbers to each other.