Oven Flaking…Help!

[JasminButtercup]

We have an electric integrated oven. Cleaner has cleaned it yesterday and said there is flaking in it.

It is now flaking all over food. It is enamel and used to be very smooth when we first got it.

It has been burning at the bottom for a while but now the roof has started flaking.

How old is it and how has it been cleaned?
Only asking as mine specifically says don’t use a steam cleaner on it, presumably because it would damage the coating.

If it’s not damaged by using products/methods that should be avoided, is it still under warranty?