Something similar yet different has happened to me ... I got a quilt dvd in the mail to watch, purchase or return. I played it but didn't want it.
Honestly I don't know if it is something that I clicked 'try this' on an email or website or if they sent it solicited cuz I'm on some 'list'
Now they keep sending me mail to pay or return, and if I don't want it to put it in the enclosed envelope ...guess what? No envelope.
I know years ago there was a mail policy that if you received something in the mail that you didn't ask for / order, you could keep it. Now with computers, etc, I don't know if I said I'd look at it ... in either case, I want to return it.
I'll scour my sewing room to see if that 'envelope' was in the original mailing but it is like looking for a needle in a ...well a room full of fabric, LOL. I know I know, I could call them and tell them to send me that special envelope.
warm quilt hugs, sue in CA