Incorrect advertising on Power Bank

Went on line looking for a power bank and saw a 100000mAh power bank advertised by Game for R199. I ordered one for myself and 3 for my friends. My order was accepted for me to pick up. I went to game to pick up the power banks and opened my package to check all was in order only to find the power banks were 10000mAh and not 100000mAh as advertised. I was told by the manager that they did not stock 100000mAh power banks and that it was a misprint by the website and that Game had nothing to do with it. My question is, why did Game accept my order if they did not stock the power banks and the price displayed is what I should pay