Why won't my script run the OnCollisionEnter/Exit code?

Question

Basically, I'm trying to create my own rendering system and the way I thought it would work would be by having a collider on my player-character (seen here) and having 4 colliders around my "blocks" (also seen here). All of the gameObjects involved have rigid bodies without gravity .

This is the code

my problem is that no matter what I try I cannot get the OnCollsionEnter()/Exit() Scripts to work. Go easy on me since I'm a beginner and it's probably a simple answer but I've searched around and can't find out how to fix it :).

PS. I've checked the Blocks and they all have the Tag they need.