Kent RO — Service is not properly done in warranty period

I have chosen best RO as I don't compromise with my health but still I am not satisfied with the product as within 9 months of purchase, it gives problems.
I have called service engineers two times but the services are not satisfactory.

Sr no KR[protected]

I again request you to kindly look into the matter. My kent RO should work properly. Instruct your engineers to give proper service. Otherwise change my product. They have changed the filters on my cost. Still it shows no RO FLOW I couldn't understand why they did not do it properly.

Do it as soon as possible.
Thanks