Premium Hike without prior correspondence

My Mom is a pensioner on Bonitas Boncap option and her premium was hiked from R577 to R5173 on the 1st August 2015 without any prior correspondence from the Medical Aid. The premium was broken into two amount i.e R2875.25 which indicated premium and R2297.75 for areas. Apparently she was billed at the highest premium for July and August 2015 despite not receiving any communication from Bonitas/Medscheme regarding Income Verification documents. I was promised the matter would be resolved once the necessary documentation was submitted and I'm still waiting for someone to get back to me.I find this to be very ********* and I'm very unhappy with the scheme .