APPLE IMAC

I know this is rather late and not sure if you can help, we purchased a Apple 27' IMAC mid 2010, we received a call back message in November 2012 to say the hard drive was faulty, we returned it and they supposedly repaired in 22 January 2013. Well it only lasted two months after the years guarantee was up and it died never to switch back on, in December 2014 we sent it back and told us the hard drive was gone and now we must pay R5000 to repair it again. My husband is unemployed and re**** on his Computer for employment. What I would like to know from Apple is how does one spend R30 000 on a computer to only last one year? How do I know if the hard drive was really replaced and was it replaced by another dud hard drive again ? Really just not fair!! <br>