IPo partial payment

Hi Sir, My Name is Subhash, I have resister in Upstox and book 1st IPO and get good return. After that I have discuss with institutional representative she told me that since you have 1.5 million in your account and it is more than sufficient for 2nd IPO you can book and I have booked. Now the issue is we can’t predict how much shares I will allot. Now institution representative pressurising me to pay 58laks how it is possible Can you please helm me in this regards