What is the purpose of a warranty if I must pay for the repais?

What a horrible company to deal with. Bought a **** eater a few months back. It doesnt work took it to Makro its still under warranty. They want to charge me R500.00 to fix it. WHAT IS THE WARRANTY FOR???. More so the **** eater brand new cost R700.00 why must i pay for something that is still under warranty according to you i damaged the item....... i have grass which is like 4 meters by 1 meter how can I possibly burn the motor with such a smal patch of grass??? Really unfair to consumers especially in these difficult financial times.