Enquiries

I have a question, I have been working for this company for 1 year 3 months, in the middle of the month I got sick, the Dr told me to take 6 days off.. Than I sent the letter to my HR they did not say anything about it, than come month end a huge amount was deducted from my salary, when I called HR they told me I no longer have sick days, what must I do guys is there's something like this in South Africa??