EaseMyTrip.com — Always asking for additional fare and Can't provide detailed invoice of the payment

I booked a flight from Easemytrip.com ( EMT[protected] during which my booking was kept on hold and was asked to pay some more money as additional fare asked by Airline. Fine, I said and paid. Later, I had to reschedule the flight and I had to pay the fare difference for new dates. Again, the ticket on hold, pay additional fare else no ticket. This is when I am selecting the dates on EMT website and it shows me the fare difference. I paid again after multiple calls with EMT. After this, I was provided invoice of the booking which is 20000 Rs less than what I paid. I asked EMT multiple times to provide me correct, detailed invoice. Promised that I will receive it but after 7 days, still not received. What sort of travel booking this EMT runs. I have no trust. I need to know details of the payment I made.