Aquaguard Water Purifier
Water doesnt seem to be pure

I have bought an aquaguard purifier 5 yrs ago.it worked very well for 2 years then we shifted to new place leaving aquaguard stopped for 3 yrs.now we have again called the person from aquaguard for its servicing.he changed candle and carbon and charged 600 rupees last week.the peoblem is that water is nottasting as good as it was before or as in through RO water. when i boiled water for my baby, there was lot of salt left behind which make me alarmed that water is not getting purified.please tell what to do.i have spent lot of money to give pure water to mykids still not satisfied.ples help.