what happens when a non cognizable offence is filed

Dear Sir, I understand that in the state of Maharashtra a complaint filed under section 504 & 506 is treated as a non cognizable and bailable offence and police can investigate the matter only after complainant gets an order / permission from a magistrate. Pl. let me know 1) is there a time limit in terms of number of days e.g. 60 days or 90 days or more days (from the date of registration of complaint with the Police station) within which the complainant has to get order / permission from the magistrate after which police can proceed with the investigation. 2) what happens to the complaint i.e. does the police close the NC complaint and the accused goes scot free if the complainant is unable to get the order / permission from the magistrate for some reason. Thanks