Discovery Stay by OYO Rooms

I'm formally complaining about our guest's unacceptable stay. Even though the booking had been fully prepaid, the room wasn't ready on arrival. Staff told the guest to freshen up in a shared area and toilet, which was inappropriate and unsanitary. After a difficult phone call later that evening, a room was finally arranged, but it was shabby, with dirty walls and a broken toilet seat. The unprofessional treatment meant we changed hotels. We demand a full refund of the prepaid amount of [Amount] because the service was not provided and the accommodation was not habitable. Please confirm immediately how this refund will be processed.