Leanspa Did not receive anything but a torn, empty envelope but Leanspa refuses to credit me with $79.99 , Internet

When my credit card showed a billing for $79.99 for merchandise I did not receive,
I called Leanspa to request credit and to cancel my account.  I had only wanted the trial anyway.  The post office delivered an empty, torn manila envelope with their (P.O) stamp stating the envelope was torn and contents missing. I mailed
the envelope to Leanspa, but the billing remains on my credit card.
 My mistake was not making a copy of the damaged envelope.  I can't prove that I did not receive the merchandise and they are unreasonable about the return of my money.  I also am a 78 year old lady on a limited income and I thoroughly believe they are a ripoff company.  If enough people make their complaints known maybe they will see the error of their ways.