Mazda *******

I have been a customer of Mazda for the past 3 years with my Mazda 2 still on warranty, Today my first time bringing a car out of warranty, first thing I was told was to pay R7000 for a major service, i declined this because the lady didn't even know what will i be paying for in the R7000. The next thing that happens is that they have finished with the service and if i remember the last time the car was under warranty we used to be invoiced R1300 flat for the service rendered which will usually be oil, plugs, filters, fuel plugs ext. but this time I was told that the car is required to do major service for R7000 but i declined it and they performed minor service which costed me R2000, but with little items on 4 items serviced than the last time. Please be aware of this **************** how does it happen the the parts in my vehicle that were changed cost less than R500, and i still have to pay R2000?