1. I was banned for griefing.

2. I was banned 3 days ago.

3. I got the owners permission.

Whomever the owner of the plot was needs to vouch for this.

-Vita

I gave him permission.

If you gave him permission why didn't you say anything sooner or in his original report?. Even if you gave him permission you should of known that its still against the servers rules to grief.

Well, its not griefing if the owner gives you permission. 

We need Jake to make a post on what is and is not griefing. 

The rules are pretty general. We need something more specific.

For example, let's say Player X is added to the plot. Player Y is the owner. Player Y and X build on the plot. 

Player Y gives Player X permission to destroy the building they were working on. (Assume they do not have acces to worldedit and do not wish to clear the plot).

Player X destroys or "griefs" the build.

Player X gets reported for griefing.

Player X gets banned.

And let's assume I'm someone who is totally new to gaming and have no idea what griefing is,

Could you tell me what exactly griefing is?

Just curious.

Griefing is destroying another player(s) plot creation(s) without their permission.

To be honest, I still find it griefing whether he got permission or not

As Kayla said. 

Griefing is destroying another player(s) plot creation(s) without their permission

Rocka4ever had permission. So, according to Kayla's definition. It's not griefing.

Your definition of griefing is

Destruction of anything made by another player? 

Am I not allowed to have an opinion, Nezz? Yeah she has her own definition, I don't care. Griefing is still griefing either way.