Oyo Rooms — charged excess for the room

Hi
I was staying in oyo townhouse 006 in koramangala, bangalore. While checking in the person there took rs. 5000 without providing any receipt. We later asked for the receipt at the reception, surprisingly there was another person there. We were said there is no receipt of any kind but after persistent discussion with the second person he agreed and gave us an invoice in which the amount was rs. 3000. When asked about the balance amount that we had pain in the morning we were simply ignored by saying that was another person, i have no idea who that person was nor have i got any amount to return you. The person at the reception was very rude in challenging to handle. After repeated request he has provided a new invoice in which there is an extra charge of rs. 1500 as convenience fee. I am stumped looking at this extra amount coming from nowhere. Please explain this fee being printed on the invoice the second time but not the first. Please respond at the earliest.