The fix for this is to download a new world.
Go to the LearnToMod homepage and select a world to download. (Click on the 'What's Hot' tab in the middle of the homepage then choose any world located under the heading 'Worlds' and to the right of the Worlds search button). This will clear any out of control mods and start you off fresh. This is also useful if you need to respawn for other reasons! Keep in mind that you won't be able to get your old world back.
Disconnect from your Minecraft launcher or exit out of your game and then restart your Minecraft server. Then download the world by pressing the put on server button, Wait 1 to 2 minutes and log back into Minecraft.
If this doesn't work, let support know that you tried this and it didn't work.