Smeg stove damage

I bought a very expensive gas stove, hob and oven is gas, stainless. Not even 3 months ago. The lettering on the oven knob adjuster is starting to come off. This stainless stove is being cleaned by n approved stainless oven cleaner. Hen i get in contact with Smeg, they point fingers to the cleaning material. Now, when I bought the stove 3 months ago, nor the salesman or the Smeg rep that assisted me, informed me that only a certain type or specific smeg product must be used. Noe smeg wants to charge me for the pannel. The stove was 18k and now they want to charge me again for the panel. My next dood neighbor also has a smeg stove for more than 10 years, and recommended the cleaning product to me, and theirs is still in pristine condition. Was this a reject? This brand is putting products into stores that has problems but cant man up and sort their problem out!!!This is total nonsens.