No response in regards with a warranty

I bought a laptop in December 2012 at Makro Nelspruit. On the box, a warranty of three years is offered by Pinnacle Africa/ Infrasol. About a month ago my laptop started giving problems and is not starting up anymore. I emailed to the email address given on the box, and got a response the following day. They requested a reference number for when the warranty was activated, but since I don't have that number anymore, they checked it against the serial number. The first serial number I sent through was missing a digit though, so they said it wasn't valid. Then I sent through the correct serial number, as well as the proof of purchase and a picture of the serial number. It has been almost 1-2 weeks now and I have received no further response from them. I've sent two more emals, but I am not getting any feedback back.