Fedhealth forcing clients to pay double

During 2019, TopMed and Fedhealth amalgamated. Due to this, they indicated that there was an outstadning balance that was due. During covid-19, I downgraded my medical aid and would have paid a lower premium. However, the normal premium was deducted and when I enquired why the lower premium was not deducted, I was told that it was because of the amalgamation and an amount was due to them, hence they took that amount. I tried getting a refund, but I was unsuccessful.

About 2 weeks ago, I submitted a claim to get refunded and to my suprise the entire amount was not paid. I called to enquire and received an email saying that Fedhealth deducted that very amount which they already took 2 years ago. Why is Fedhealth expecting me to pay something that was already paid for 2 years ago?

This is unacceptable and urgent assistance will be greatly appreciated.