Kent RO System — Product is not working

I bought Kent RO system 6 years back,it worked very well for first 3 years after that it is giving me lots of trouble.in this financial year also I spent almost Rs3000 for its service and they have changed the parts as well ,but all gone in vain as again the same problem re-occure.When I ask for complaint they ask for service charges every time.I am also working into service industry but never seen this kind of After sales service it is pathetic.I recommend that no one should buy Kaent RO.my contact number is [protected]