So I forgot the title of a manga, but all I can remember are:

• the manga start with the MC goes to a kind of an alterlife where they could be freed if they reach the top of the tower/wall/something like that
• there is a scene where a few people who tried to climb it getting betrayed by one of them and pushed down
  That is all I could remember
  Anyone remember anything similiar?
  Thanks

Not sure but from your description remind me this particular manga, Sennen Meikyuu no Nana Ouji. does it the manga you looking for?

Be kind or get banned