Bottom Line Books Bottom Line Publications received books I did not order but was billed for, Internet

I ordered one book from Bottom Line, but decided to return it.  Then, without asking for it, I received another book; one that I had not ordered.  There were no instructions on HOW to return either one,  nor was there a telephone number by which I could contact them.  I got on-line to see if I could find a contact number, and instead found a bevy of complaints similar to mine. 

I am sending the books back anyway, but keeping a complete record of any correspondence and the USPS return information as well as a record of any attempts to contact them by any other method,  (as a CYA precaution) because it is my understanding that this company duns you for payment whether you've already paid, sent the merchandise back, sent correspondence, etc.