A Mysterious Kit Return

While looking for some parts I found this note:

And the back:

I had gotten this note in a parcel with an unbuilt PK-4 keyer kit many years ago.  It had been purchased from a person who used to resell my kits.  There was absolutely no clue as to who sent the kit back.  No return address, no invoice, no email address.  Just the note.

First, the nastygrammer was correct, the printed manual returned with the kit didn't have page 10.  The fellow who sold this kit died long ago so can't be asked about it.  I stopped including printed manuals in the 20th century.

(see:  https://wb9kzy.blogspot.com/2022/06/no-printed-documentation-with-kit.html

Second, I didn't understand why someone would pay to return an item and then not identify themselves in any way or even ask for a refund.  Just enclosing a nastygram in all caps must have been enough for them to feel better ?

Third, the manuals for all the kits are online for downloading/viewing in pdf format.  I guess I assumed that buyers would look at them first and then buy if they liked what they saw. 

Fourth, why was the kit sent to me ?  The buyer purchased the kit from a reseller, why not send it back to them ? 

I hope that people don't suffer in silence with a kit purchase, if something is wrong I'd like to try to make it right.  And unidentified raging doesn't do anyone any good, right ?

Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm