In the sever Mineverse on the mini game survival I decided to go to the nether. When I walked back into my portal it took me to another portal that had protected blocks surrounding it. I can't break blocks or place things or go to my inventory or type. I had to hit control alt delete to get out of minecraft. How do I get out
Why won't my nether portal bring me back where I left? explains what's going on. I can't say whether the portal was constructed this way on purpose and, if so, whether it was done by admins or griefers.
To escape from the portal, you could kill yourself with /kill but you would, of course, lose all your items. The alternative would be to contact an op or admin and have them teleport you out/ give you permission to break blocks.