recently i found one new housing development, was advertised at 500k, when i went to office, i was told price increased 100k just in 3 months. can developer naik harga suka-suka hati? does it against any rule / regulation?

second question, i went the office this evening, the advertisement of 500k again just published in mudah.my by developer. how can they manipulate price like this?

please do enlighten me..