Collision based on colour

You have 2 conflicting variables:

  1. Color

  2. MyColor

Change all your Color to MyColor and remove Color variables so won’t get confused and made mistakes.

In short, you are setting the colors of the ff.:

Wall: MyColor
Ball: MyColor

But then you are getting the wrong variable from Wall_BP:

Wall: Color (shouldn't it be MyColor and not Color ?)
Ball: MyColor