the guards wont let me in , and the underwater way is blocked. Is there around this or did i break the game?

In my game, I remember the way through the underwater bit being quite difficult to navigate - it looked like it was blocked but it wasn't. With that said, it did seem to get blocked once I'd completed that part of the quest so it could be a bug.

Have you looked at any youtube videos of that bit of the quest just to be sure?

thanks ill try harder at swimming

any other ways to complete this quest, the the gaurds want to kill me to im scewred, i need to find a old man in village, ive seen him in vidoes but he is no where to be found in my game

I think you just learned a valuable lesson about using multiple saves.