Have you tried using a different client? What is the error message that it shows? Have you updated Java? Are you using 1.8?
I think you might be stuck in a block on Prison. Try to email [email protected] to teleport you to spawn.
I think the problem is the certain place you are is a laggy place which causes you to always be "Loading Terrian" It happened to me on a different server and the owner had to tp me to spawn contact a server admin.
Try changing your render distance, changing your graphics to fast, and changing smooth lighting to off.