Medicross Roodepoort claiming money already paid to them and handing the account to lawyers!

In 2019 i went to Medicross Roodepoort as i was sick. The doctor, Dr. van Zyl gave me some meds which i had to contact him after a week to alert am not getting better. He asked me to come and see him again which i asked if this is a separate consultation and he said no, it is just a follow up and i must come straight to his office. I did that and got helped however months after this had occured i've been receiving calls and smses that i owe Medicredit. I tried explaining this which seems to be fine only when we are on the phone. Now am being threatened by lawyers telling me my account has been handed over! It is really not fair for businesses such as Medicross to just hand over a matter that was never handled properly internally. So now am supposed to pay R566.39 from R464.04 of which i paid this amount on my first consultation. This is utter nonsense and we should not be treated like this! I can't get my credit ruined over this amount and i hate the fact that what's recorded on the confidential main i received is when i was contacted but they do not show my responses.