No communication

I joined Bonitas in January when I started my new job. I was not told how much I would contribute monthly when I received my payslip in January R1200 was deducted. I then received my February payslip and to my surprise R1700 was deducted by the medical aid and another R500 was taken, I assume it was for last month. I am very dissapointed because they have my contact details they were suppose to to call me and explain that the was an error last month and ask my permission to deduct last months money. I do my budget before I get my salary so that I dont over spent. They were suppose to call me and we make an agreement or an arrangement. Really angry thinking of changing it.....