Lg Microwave rusts... Model ms4295dis

Took in a LG microwave that was under 2 years old that started rusting in the cavity Bought a premium model with extended warranty thinking it would last... Cant see how it's my fault yet game says warranty void... Previous microwave lasted us years but packed up yet no rust on it No other appliances in the kitchen seem to rust but the microwave The way they handled it was so unprofessional... Wont be supporting them or LG In the future