Netcare review: hospital account

I underwent an operation on 25 April 2019. I was suppose to report to the hospital at 12:00. Authorisation was obtained for a one day stay in the hospital. I was discharged the next day before 1:00. The hospital charged me for 2 days. Both my medical aid and the Gap cover insurance is of the opinion that I should only have been charged for one day. I have been in contact with the hospital's accounts section both telepathically and by email. They are adamant that this is how their system is programmed.

Please assist.

Hospital customer no: [protected]