Pensionable Income ignored

My daughter is at Bonitas Boncap medical since 2009. She is a Representative for a company and earns a small salary with commission and travel allowance. Suddenly BonCap increased her monthly contribution from R821 to R1495 because according to the consultant her past contributions were calculated incorrectly. The contributions are calculated on MONTHLY INCOME and not on pensionable income which is totally untrue according to their web adverti*****t. Since when can a medical fund ignores a law enforcement? I also experienced numerous problems with their administration. I was debited with an amount of R1834 in January because they did not updated their systems since 23/3/2015 and 23/11/2015 with the correct cellphone numbers and email addresses and an email was send to an email address that changed 4 years ago. A marriage certificate was send with the documents but they still ignore the fact that her surname changed. I made 6 calls to their service centre and spoke to different consultants and they still did not went through all the documents which was send in 2015 meaning I was not advise about all the outstanding documents each and every time I made a call.