Does anybody know how IDP works?

Does anybody know how IDP works? First I confirmed with a student that they take 7500 rupees for applying to those universities which are not their client. But today that same student said that you have to pay application fees of college and if accepted then pay 7500 to idp for further process. But today my counsellor said that you have to pay application fees of all universities taht you are applying in. It doesn't matter if they are our client or not, we'll try to get an application waiver wherever we can. And after getting accepted you have to pay nothing. Why this shit is so confusing? And they are making me sign an agreement that I'm scared to do as it mentions something about 7500 there.