Had a similar incident with a washing machine a few years ago. Bought it at a big global store. The customer service they provide have been shit regarding other things I’ve bought there (including a TV, but that’s another story).
I collected it at the store, the man at the loading deck asked if we were here to collect a Bosch. I handed over the receipt, he went to get the machine and placed it outside the door. I asked if he could atleast roll it down the ramp for me with his pallet lift, but no he couldn’t… I even said I could do it myself if I could borrow the lift. But no, he just went in and closed the doors. So me and my dad had to carry it down the ramp and lift it into the trailer ourselves. It weighed a fking ton!
When we got it home and finally got it in place, unwrapped and connected (wished I had a crane!) I noticed it looked different to the one in the store. Same brand though. Turns out the man at the loading dock gave us a bigger and better washing machine that cost £999, not the one I payed £399 for.
After I calmed down I decided that it would be really easy for them to realise their mistake. My name, phone number, address etc were on the receipt, so if they called I would tell them to send that guy from the loading deck. He could disconnect it himself, wrap it up and load this heavy beast of a machine himself! They never called 
