Why have a medical aid when i have to pay out of my own pocket.

i was in Jakaranda Hospital from 21/05/2020 to 30/06/2020. i was discharged a day early as Discovery had called the hospital to advise i had run out of funds. I was discharged then i received a statement from the hospital stating i owe R11 172.70. As far as i knew as i had been discharged a day earlier and had nothing else to pay except medication. i advised i would not afford to pay that amount and was told i exceeded my stay there, how when they called to get me discharged and said if i stay longer id pay from my own pocket.