Royal Enfield — due to corrosion or rust in the end of silencer getting tired off

I purchased a royal enfield – 350 classic bike for my son and it was delivered on 17th may, 2017 from tecnic motors agara, ring road, bangalore. Now from jan -2019 we noticed rust type of thing at the end of silencer and now almost it looks like as if it is tored (Punctured) at two spots.
Today, i went to dealer and asked why it has happened to our bike only or is it regular with all the re – 350 classic bikes. His explanation, i was unable to follow. I asked him to replace with new silencer (Part of). He asked approximately rs.2500/- as the warranty which is for two years only. If it would have been in may-19, he could have done free of cost. But this rusting we noticed in jan-19 only, i thought it will go if bike is cleaned. So this issue was in warranty period only.
I request you through this mail give instruction to technic motor, hsr layout, ring road, agara, bangalore or any dealer in bangalore to replace the required silencer (Part of) at the earliest.

Expecting a positive response from your side at the earliest.