If you ordered from an online vendor that claimed in the shopping cart system that product X was in stock... and then the vendor later emailed you to say product X was actually not in stock and you'd have to wait 2-4 weeks for it... and you noticed that the online cart system continued to claim that product X was in stock... would you broadly classify that as "bait and switch" or simply "incompetence" ?
I read through the Competition Act and the situation is not completely applicable, although the saving proposed of substituting functionally equivalent product at the originally offered price would suit me just fine.
It's extremely unprofessional in any case.