How can we get money back that was paid wrongly.

My husband is an Eskom pensioner. He do have the medical aid. Three months ago we asked if they can assist us to lower the bonitas penalty fee because we are only pensioners. All of a sudden they took nearly a 100% increase on the penalty amount. We already suffer now 3 months to get our money back. Bonitas say EPPF must reverse it from their account and pau it back, and EPPF say Bonitas must pay it back to us. I sent a lot of emails also but mever get feedback from anyone. Wish somebody can help us to get our money back. We need it urgently.