AO Smith — water geyser

Address:

Ghaziabad, Uttar Pradesh, 201010

I had purchased a 25 litre water geyser last winter with 2 year + 2 year extended warranty.
Immediately after using for 3-5 consecutive months, there was a bad ouder smelly water from the geyser.

I had then complaint at call centre and they confirmed that the water tank is required to be cleaned. I ask ed if any charges. They confirmed it's free service.
The agent visited and cleaned the water tank for no charges and had given a service slip.

Now again the same instance is repeated, now when i called the call centre, they claim for re 400 as service charges and confirm that company has changed to rules in feb before gst. There is no reply to my query that the customer who was committed foe free service should be informed. No reply yet after 24 hrs.
I am stuck, not able to use the product. Please help.
Also they say, this will happen every time and charges have to be paid. I did not face any such issue over last 15 years with other gysers as used. This is absolutely a cheat with the customer.