4 May 2013 at 13:57
The R175 that is being taken off is for PAYE (Pay-As-You-Earn) which needs to be deducted from your earnings each month. The company that you write for in not aware that you do not earn any other income and has a duty to deduct this tax and pay it over to SARS. You can apply for a Tax Directive with SARS to have them not deduct any amounts. Otherwise at the end of the tax year they will send you an IRP5 for which you will use to submit a tax return and the PAYE will be refunded to you because you don't earn enough to actually be paying tax.
You can register for a tax number by following this easy guide - Registration Guide