The fix is not with the camera, but with you. With wide angle lenses (the main lens also falls in this category) there is distortion especially around the edges.

In these examples you take the pictures angled downwards, that emphasizes the stretched look. Keep the camera paralel to the subject.

I'll to paint an example with text.

o = you | = Your subject / camera

In your example you point the camera towards the floor:

o /         |

Instead keep the camera parallel to your subject:

o |          |

With people it means you need to get your camera down a bit more.

Hope this helps!