Healthy Online Services Non-Received Product Scam for Online purchases Scottsdale, Arizona

My story is the same as most of the others writing about Healthy Online Services.  Orderd the 'free' trial paying only shipping costs for both products.  Received only one of the products.  Charge of $83.95 appeared on credit card statement which I promptly disputed and went thru the process-ultimately it was removed.  Now, months later, as others have stated, a 'demand for payment' arrived and along with the original amount they have added a $50.00 'chargeback fee'.  The usual threat to send it to a debt collection agency and that it 'may' have a negative effect on your score.
The address that payment is to be sent-7904 E. Chaparral Rd. #A110-146 is a mail drop at UPS Store #2700 from which it undoubtedly is picked-up and forwarded to who-knows-where.  They are not listed with the Arizona BBB or State Corporation Commission or in Minnesota.  I believe they rely on intimidation and anyone who responds with payment they are that much ahead.  I advised them in my response that those agencies in AZ. & MN. have been forwarded the information along with the Attorneys General of AZ., MN. & WA.  I have read the Fair Debt Collection Act and will follow it precisely if I am contacted by a debt collector.