Highway ******* of a Pensioner R4000

My mom is on the Keycare Plus option. She is a pensioner. My sister opened this plan for her and has happily been paying R1400 for a few years. She discovered yesterday that they had been deducting R4000 for the past 8 months without her knowledge. Given they email a review of the customers income (my 70 year old mom who has been on a pension for the past 10years). Emails go unnoticed many times, especially if they aren’t work oriented and get sent to the updates or promotions folders of your email accounts.due to no response to their email they decided to bump (my 70 year old mom) the amount up to the maximum payment of R4000 without a phone call or a message. Shouldn’t they use common sense that the customer is a pensioner and will possibly never see the amount of R4000 from a government pension 😱😱. Discovery refuse to reimburse my sister forcing us to go through other avenues. Has anyone ever experienced this and what did you do to get reimbursed?