Faulty tax certificate

I am a relatively happy Medshield member, but this is under major strain due to errors on my tax certificate. The error will cost me thousands in unnecessary tax payable to SARS. I requested correction from Medshield 3 months ago. I have followed-up at reasonable intervals, and for the last 4 weeks I have resorted to begging. Medshield has still not provided a corrected tax certificate.