Part Occupancy certificate

Actually I am purchasing the property in Mumbai but the building has obtained part occupation certificate(Bhag Bhogwata cha Dakhla - in Marathi) which clearly mentions that "the building premises has been completed on land bearing CTS no. ...123 ...according to approved plan no. ...Xyz... (i.e. stilt +7 th floor) under the supervision of licenced architect, engineer and supervisor having Lic. No. ABC" but when I had gone to see the flat the building was made till ground+4th floor and my flat was at 4th floor. The land survey no.(CTS no.) mentioned in the agreement and on the occupancy certificate is same. And also nationalised banks are giving loans on it. Now my question is, see actually we know that any municipal corporation will never break a building so easily.....and also what I feel is municipality has given occupancy certificate to the building inadvertantly but the building is constructed up to 4th floor and that too part occupancy certificate is given upto 7th floor. Now the building is 12 year old. I m very much confused since i have paid booking amount of Rs. 50000 and also all brokers are insisting me that not to cancel this deal since I may not get any flat at this place with Oc. Now what I shud do....since such kind of fraud work is only made by the govt. Whether i shud go for this flat or not...? Kindly do my hard earned money will go into vain.