Overcharging customers even after they’ve sent required documents

Discovery Health announced the price adjustment of their key care plus medical aid plan which will take effect in October. We were requested to send our income verification documentation. I sent my documents as required. Via email and i uploaded them on my Discovery Health app as soon as I received the email about the price adjustment. There was communication after the submission of documents. I am now being debited R3 687 for a plan I should be paying R1 817. Why am I being overcharged after i have submitted the necessary documents. I can’t afford to pay R3687 monthly on an internship salary while living in South Africa economy. I’m afraid discovery will be losing a customer.