Neff Hob Markings

Hi
We have a Neff gas hob which is three years old. The control markings have started to come off. I have contacted Neff who say that they only come off if you have cleaned the hob with anything other than soapy
water.
The controls have always been cleaned very carefully with soapy water as it is quite clear that it would be easy to rub the markings off with anything abrasive.
Has anyone any experience of this. I don`t really expect to have to pay £100 for a new top. Negates the reason to buy Neff in the first place i.e qaulity of product.

Many Thanks
Jason