Swiss Science Scammed for $169.95 Clearwater, Florida

I replied to a promotional weight loss sample from Swiss Science for $3.95.  It was charged to my Mastercard.  Within a few weeks I received 3 bottles of weight loss pills and/or supplements along with some type of calculator.  I thought good, I'll give it a try.  Then I see that my Mastercard was charged an additional $169.95 two days after the $3.95 charge.  I had received no other packages.  I called to see what happened.  Of course, I was unable to get through their 866 calling number with the first dozen calls. When I finally reached a non-American person at the end of the line, he told me I was wrong and that they never offered "samples".  I asked what the $3.95 charge was for and he gave me some type of website with a doctor's theory on weight loss.  That, he said, was all I paid for.  I asked for full reimbursement to my account.  He said he was unable to do that but would refund only half until the merchandise was returned.  A week later and this charge has not been reversed.  I sent my package with a return receipt but I suspect they know their way around that too.  So far I am out a total of $173.90.  I read that website carefully and there was no way of knowing about the scam.  I can't even find that website anymore.  I see others have posted on Swiss Science only their charges were $4.95 and then $149.95.