Generator under guarantee means nothing

On 12 August 2015 I returned a Grip Generator to Builders Express in Middelburg Mpumalanga due to the fact that it is not generating electricity, I bought the generator from Builders Express in Middelburg Mpumalaanga on 30 January 2015. The generator is still under guarantee that is why they had no problem to take the generator. On 19 August 2015 I received a call from Builders Express stating that it will cost me R5000 to repair the generator that is still under guarantee. Or I will have to pay R500 for transport and faultfinding to get MY generator back. I really think that it is pathetic to expect me to pay ANYTHING for a product that is still under guarantee. Clearly a guarantee at Builders Express is worth NOTHING!! If this is the service that they give us, I will have no choice but to inform family and friends not to buy ANYTHING from Builders Express that is under guarantee because it is not even worth the paper it is written on. Thank you for the most PATHETIC SERVICE that I have EVER had!!! If you want to look into this issue my customer repair number is 7010 that is now if you care about your clients as you say you do!!!