Discovery medical aid offers no assistance and want to deduct most of my salary

I have been a member of discovery medical aid for a long time and my premiums are always paid via debit order every month. This morning at 8am I was informed through a whatsapp message by discovery that my premiums have almost doubled because they dispute my earnings and will be deducting the almost doubled amount on 2 January 2024. This new amount is almost my entire salary. I have sent my payslips to discovery to be allocated in the correct premiums bracket but this will take 10 days to review. I do not have 10 days to wait for a salary review when the money will be deducted on the 2nd. I am a single mother with a single salary and cannot afford this. My kids need to eat. How can they just decide what I earn when the evidence is black and white in my payslip? Furthermore I tried to contact them via phone call from 8am till 11.32am for them to put the phone down on me again. What a waste of airtime and my problem is not solved. I them spoke to a consultant in whatsapp and all they can say is they apologize but still taking their new assumed amount of money. I'm a very disappointed customer and feel I have been treated so unfairly after being so loyal to discovery with my monthly contributions.