[Resolved]  Pureit / Hindustan Unilever — Servicing

I have pureit mineral ro uv classic, i have to spend 4000 to 5000 every year for maintenance it's about 50%of machine cost. Recently on 02/07/2020 i called them for servicing, one of the person came he changed sediment filter and charged 550 but problem of slow water rate didn't solved, he again came on 10/07/2020 this time he said me to change membrane for that he sold one gkk kit to me but he changed only membrane, that's fine machine started working. But on 06/08/2020 red signal shown by machine, they again came and changed gkk but this time they said now your pump is not working. I was confused because it was working before changing gkk then why it is not working now. They replied its happen some time when we change gkk. So is it company policy that every time you have to say that some part is not working and ask customer to buy?