forum messed up

well i dont know where to start but he goes,my forum last couple of days is doing its own thing,if i install a skin from admin panel or hitskin it not what it is supposed to be.then if i try to make any changes to colors or width or any minor mods it does its own thing .know matter what i do its screwed up ive never had these probs before.there has been a crawleror spider from russia coming and going for a week or more now and shows as a guest in the admin and bottom of my forum i think this board is hacked or something is seriuosly wrong i need help to get this forum of mine back to its secure default state and in my control.
http://neonappz.forumotion.co.uk
please someone take a look and see the mess its in.
my forum skin was invision pro from hitskin,thanks

Maybe in one of these topics you'll find your answer, your mistake...
https://help.forumotion.com/t51-internet-security-on-your-forum-habits-to-be-avoided
https://help.forumotion.com/t75418-my-forum-was-hacked

thanks for your repl and those points have been observed by me that im aware of ,and not being rude but you say no hacker can hack a forumotion forum well thats not true i know of peeps forums getting hacked and back on topic your advice still does not resolve my present problem this forum is screwed up and im asking for help here and im no expert i might add thanks