"Temu" falls 99% discount on items

Currently they do have a promtion on of ist item on 99% discount and 5 items on 55% discount.When ever you select a expensive item on 99% and cheap items on 55 % then the item you choose on 99 % will be out of stock. After numerous e mails to Temu in this regard they still continue to advertise it although they can't fullfill there promises.I did tried various expensive items on 99% discount but the results remain the same. They claim that there are no flaws in there system but failed to proof me wrong.