[Nyx]

So for example. I order something and just say I felt sick?

Social Engineering is all about manipulating the person or company to your own benefit. There are plenty of methods and it isn't cut and dry. You could call and say you just bought a pizza and felt sick afterwards. Or you ordered a pizza and they got the order totally wrong. There are limitless methods you can use you just have to be creative with it.

Coming back to this post, would they not ask for a order number etc?

Then you come up with a real clever reason for why you've lost your order number.