additioanl charge for the due amount

Location/place: Bangalore

Name of company/service: VANDANA MARUEL

I have booked one flat in Bangalore developed by VANDANA MARUEL. I need completion certifcate for the floor in which i have booked, but these builders are not providing me the same. I am following up with them for completion certiifcate for more than 45 days now, but all the time I get only one response that they dont have completion certificate and asking me to switch to other bank where they have tie up and that bank wont ask for completion certificate else they will charge additioanl charge for the due amount.