Just a quick note to share my experience....
I ordered a S8 Ultra on Black Friday from a local company, the deal was very good, but not an obvious error. The price I paid was R17k. Amazon was doing deals for ~$900 excl shipping.
The tablet arrived on Tuesday, and about 5 hours later I got a call to say "Whoops, we made a mistake... That price was for the standard, not the Ultra. Can we please send our courier to collect, have you opened it?"
I said I'd opened it, so they suggested I pay in the difference of R8k for the price it was supposed to be. I said that is unreasonable, and I reject that proposal. They then ask how much I would pay in... I obviously said zero.
I've obviously had orders cancelled before, and I accept that 9 times out of 10 - if a deal looks too good to be true, it'll probably not be honoured.... Never had this before though