"No offense, but are you high?
This is NOT a Singer sewing machine. It was made by the _____________ Co. in _______________________
In all honesty,It should NOT valued at $_______ (unless it has some amazing connection to a historical person/place/event)
I'm sorry if you were misled by someone else regarding this machine in the first place but I thought I would at least give you the opportunity to be aware of the truth.
Signed ________
There ya go, CL form letter