Whirlpool India — Wrong charges on AC service which is covered under AMC

Few days back whirlpool AC service team had visited my house on my complaint regarding cooling issue with my AC which is under AMC. They had told me that air valve of my AC outdoor unit is not working properly and it needs to be replaced. For that they had charged Rs 950 from me. They said its having rubber part and thats why it is not covered under AMC. But in actual there is no rubber compnent inside it and it is totally made up of copper and brass only. I am attaching its photo for your reference.

I have send multiple emails to whirlpool at many email ids but i have not received any update from them. Can you please look into the matter and if it is covered under AMC then take necessary action to get back my amount.