Complaint about Breach of Contract

I bought Sansui Tablet 7inch at Hifi Corporation on the 10 August 2015. On the 08 September I took it back to the store because it had a problem with a charger. The sales person who assisted me said he could not change it because the Sim card was stuck inside. He also said that if they take it for repairs I will be liable for the payment. <br> <br> My question is what is the policy regarding the warranty and guarantee of the product. Is it the company policy not to fix their products while they are still guarantee. <br> <br> Please respond to my concern.