Senior citizens often use a very high gas flame while heating, and also keep the gas on for a longer time
Usually the stainless steel vessel will only become black in color
However it appears that the stainless steel vessels purchased on amazon have only a thin layer of steel, and have disintegrated when heated at a high temperature for a longer period of time.
Now after wasting many hours, cleaning the vessel, some of the black coating has been removed, but now when water is put in the stainless steel vessel, it is getting rusted, and is not safe for cooking food.
So new utensils will have to be purchased for cooking food.