worthless guarantees

Good Day, I purchased an new angle grinder at Game Store's which came with a so-called one year warranty, we used it twice, for the purpose it was supposed to be designed for, after 4 months the gears packed up -we took it back and were told that even though it comes with a 1 year guarantee we have to pay for the repairs as they don't cover "wear and tear" I had this same response from Izuzu when we bought a brand new bakkie from them, the elbows holding the tailgate wore away before even its first service ! which resulted in damage to the brand new tailgate -they said the same thing, ie. the guarantee doesn't cover "wear and tear" -how can there be wear and tear on brand new items ?? -I complained to Game head office -all I get from them is an automated response over and over, saying they are sorry and will get back to me- its been over a month and still no-one has had the courtesy to get back to me -I have heard from others that this is a new way some companies get out of honoring their warranties, as wear and tear can cover any and all things -which basically means the guarantees are worthless -where does the consumer counsil stand on this and I wonder just how wide spread this is