Well, it could be a sort of coincidence :
- the app was published in june 2012 with no update
- the users were 20 to have kindly rated it
- in december 2012, I received the offer of the marketer and refused it
- in december 2012, some days after having replied, the app received 37 bad ratings (1) and comments like "don't download this", "stupid app", etc.