Okay, so what exactly is going on?
What did I do? What rule did I break? And why exactly from what I did that broke the rules?

Edit:

In game name: 5lo0o0od

Reason for your ban: X-ray.

Why should you be unbanned:
I was in a stronghold, walking around and mining some stone bricks. I started digging down since I started walking in circles and could not find the end portal. Found a tunnel that was already built kept digging forward in that tunnel, found a huge chunk of diamonds. There was a left turn in the tunnel, went down there, there was some iron as I kept digging, mined it, hit bedrock and found another chunk of diamond.
When I went back, I decided to dig a new tunnel on the other side since I was a couple of blocks above bedrock a that is where diamonds are, found some more diamonds. At that point, I was feeling like the luckiest guy around and was digging my way out to the cavern until admin decided to tp and kill me.
I was way at the bottom by the bedrocks. That is where diamonds are. I had my brightness at full and didn't need torches since it was all semi-random tunnels.
I was surprised there was that much clumped up diamonds myself. I thought only coal can appear in such lots, but I didn't use any x-ray.

"You got caught xraying, it was very obvious too."

I explained what happened and told you that I did not use any kind of x-ray.