Faber — Water purifier service (in warranty)

I purchased Faber water purifier from Amazon in February 2021 and it was stop working in May month, I have complaint for the same(product is in warranty) and exactly after one month after calling many a times to customer care and service center they sent a service man, he opened the purifier, after spending an hour he did not even understand what is the problem.
Then he said a part need to be replaced and he will after 2 days with that part.
It is been 2 weeks he did not turned up, we are continuously calling/following them multiple times.
may be Faber is not capable to run the water purifier business and provide proper after sales service.

I do not know Why do companies mention the word 'Warranty' when they does not even understand the meaning of it and not able to service...