New Stove Plates starts rusting

Over the past 40 years, we've bought several Defy appliances and never had any problems. Unfortunately, in April this year, we purchased a new Defy stove, and within the first two months, the plates started to get marks. We insisted that a Defy technician come out. The technician, Richard, came out today and app**** a black polish, saying it is not supposed to happen again. Remember that the stove is installed in a flat in Pretoria, which is not a coastal region and is not in the rainy season either. The stove wasn't used much and was cleaned with general dishwashing liquid and a cloth. It is the 5th Defy stove. We have bought it for many years for different properties and never had this problem. - New stove plates should not rust within 10 weeks under normal conditions. Rusting can occur due to several factors, such as exposure to moisture, improper cleaning, or poor-quality materials.