Kent RO — faulty service

Address:

Gurgaon, Haryana

there was a leakage in filter and we called service guy from kent named GAurav sector-4 gurgaon. he came and changed 2 filters and one more part.
1. there was no date or anything printed on filters.
2. the drainage of waste water has gone 5 times of filtered water.
3. we want someone else senior to come and see as we doubt his service.
as we are working so the service guy is not ready to come before 9am and after 7pm..Also he is saying that service charges will again will be charged if we wont call him in another 10 days.

I don't understand the type of service and spare parts such a big company is gving to us.

want someone else to come and check our RO after 7 pm.