Lizzy - thanks for that suggestion - I checked - and the serial number
is different
so my theory is incorrect - either the quest is not compatible with me
- or they need to go into the lemonade business.

how about gently scratching the machine in a a few places - just normal
wear and tear scratches, my 10 months old machine certainly has a few.
Take photos and write them all down. You could also try and put a tiny
blob of nail varnish somewhere hidden too. I think they really should
give you a refund, but let's face it replacement is way more likely, so
I'd do these things send the letter than demands a return, but be
prepared that they may not do that and at least you'll have back up to
determine if it's the same machine or not.

I've been so lucky with my similar problems, you're right about how they
replace just the machine part but as I did it via the shop I bought
from, I took the machine in only once they had the machine to replace it
with and had both of them within sight during the exchange - they also
gave me a 50 dollar gift card for the store, I'm going to be sticking
with this dealership!

Cheers
Anne