Indian Army — fraud by a person in his name jaikishan

Sir i see a advertising on olx so i interested in mobile one+ 6 then jaikishan name men give me his no. I contect with him and he will pay me 17000 rs pay to mobile i say done then he say half payment will give now and other after phone delivery next a person call. Me currier boy say you must pay full payment then mobile give you. I give him full payment then he say i will done payment then he will say extra 7550 transfer for company police i will pay then another say pay 7550 i will pay bt then he say 5000 extra pay for i will not give and say to return parcel sir plz help