Macbook Laptop Repairs

I sent my laptop to Istore in Gateway Durban for repairs. Istore gave me a quotation of R 9 365.72 to replace the damaged display unit. I accepted the quote and asked them to repair the laptop, I then got a message from Istore saying that the laptop is repaired and I must come and collect it. I then went to Istore only to find that the laptop is still not repaired and this has happened on three occasions. I recently got another quote from Istore which is about R1000 more than the previous quote but for the same repairs to be carried out. Istore has had the laptop for over a month now and I cannot even work without my laptop and I am now loosing business opportunities. I am not happy with Istore service and I require them to justify the matter urgently.