Do not answer unknown calls and do not call them back. Consider getting a call blocking device (or app for your cell phone)-they're available online and start around $45. http://800notes.com/nb/search?q=call+blockers
Someone from this number calls me every day. I don't know who they are and I won't answer, but every day they harass me with unwanted calls. I have a private, unlisted (and paid for) phone number so I don't know how they got my number.
Yes, I have ordered and received supplements from Canada about 4 years ago. I get called every few months since then. They actually leave a message and a working phone number. No, the supplements didn't get the best results.