IFB Industries — Engineer forcing to buy descale powder and not fixing machine

Machine was making sound during washing. Arranged service and service person said suspension part will be changed and before that tub needs to be descaled and said it will cost 2000 for the descale powder as 10 packs need to be put.I denied becoz 1 pakt is put in 3 months but he didn't agreed and left. I ordered descale powder and again called for service. The same person came and said the powder that I have purchased is local and fake and refused to put the Powder and insisted that I have to buy the Powder from him only and he made me speak to his supervisor and he also said the same thing. I need help bcoz IFB is forcing me to pay 2000 for descaling powder and not repairing my machine which is in warranty.