Every housing developer must apply to KPKT for approval to put up advertisement.

At the bottom of the advertisement, there must be small notes with all the mandated info.

Check for the type of units for sale, min price, max price.

Developer cannot sell over the max price, at least cannot put it on a standard SPA.

If they want to sell something over their advertised price, they usually collect a certain sum undertable or make it a subsale.

Ask from developer's office lah.

If don't have, you can report them to KPKT.