Disabled parking stickers for everyone?

AS a disabled person I would like to ask the following:

1. When is a person classified as disabled?

2. To what degree must a person be disabled to qualify for a disabled sticker?

The reason I ask these questions is that when I became disabled I had to get a doctor’s letter stating my disability, in order for me to apply for the sticker at the municipal offices – and I had to pay for my sticker.

The sticker has all my details: Name, ID and a reference number.

There are people out there who have stickers who is not disabled. How did they obtain these?

I see that one can now buy a plain disabled sticker just about anywhere and I personally know people who use the store bought sticker to access easy parking!

So, are these store bought stickers legal?

If not, why do the authorities not take action to bring these people to book?

D JOOSTE