Reversed payments and incompetency

I, Letitia Pullen, was hospitalized in December 2020. My Lancet account was paid almost in full by Bonitas, I had a small fee to pay in, in January. In April I was informed by Lancet that I owe them R3383.70 for December 2020 when I was in hospital. I phoned Bonitas and they informed me that there has been a payment reversal on the system and they will send it to their IT department to do the correction and I should phone back in 7 days to follow up. After several follow ups and promises of payment that will be scheduled, the account has still not been paid and Lancet has handed me over. This is inacceptable, as the account has been paid, how can they just reverse a payment 3 months after it has been paid! This has now cost me a lot of money as I've been phoning back and forth between Bonitas and Lancet for 3 months just to get Bonitas to do as they promise!