TAKING ADVANTAGE OF ILLITERATES - AFRICAN BANK

My brother bought a fridge for R4000 at Ellerines in Rustenburg on 16 July 2013. All cost including HP was R5114 that the sales person explained to him and instalment of R446 for 12 months. Since he is illiterate, he signed as per the explanation he got from the sales person. The insurance was never disclosed or interest. The debit order started 30 Aug 2013 until to date. Last year 2014 he went to Ellerines at Rustenburg to complain that 12 months is overdue, Ellerines was nowhere to be found. Last month he decided to stop payment and reversed the deduction. To his surprise, he is now getting threatening messages from African Bank, that he is breaching the contract. What must he do?