they told me to cancel it or wait more then aliexpress 75 days delivery limit so basically its scam

That’s not what they told you though. They told you to extend shipping time which is the time they have to submit a tracking number to the system, which is like 12 days on Ali I believe.

It’s not unusual for sellers on Ali during big sales to run out of stock, yes I agree it’s a bit questionable to sell things you don’t have readily in stock, but it’s not exclusive to KZ. For example a lot of people are waiting for their Dawn Pro DAC to get shipped from Moondrop, which is a much more respectable company in the chinese IEM world, so they’ll have to either do the same and ask for extension or… yeah I don’t know what else - but their Ali store listing for Dawn Pro has some negative reviews with people stating that they’ve just outright submitted a fake tracking number to avoid having to ask people for extension. Is that true? Who knows.