OUTSTANDING FEE DUE - NO WAY TO PAY

My son had an accident at work and was rushed to the Emergency room at the Brenthurst Clinic in March this year. I was unaware that the medical aid had not settled the first amount due of R355 and only this week (4th week in September 2019) did my receive a call from a collection agency demanding payment. I called the Brenthurst Clinic accounts who advised me that the account is clear. My son was advised that we'd receive an e-mail from the collection agents. None received to date. Please assist as I am getting nowhere.