is it possible to buy more than 1 bank chest and if you can is there a way to open them/

You can expand the chest from a single chest to a double, but past that im pretty sure you cannot buy more

i bought 2 more chest

To my knowledge there is, currently, no way to buy more then a double chest. If you would like to suggest it to the prison, you can make a post in the prison suggestions thread.

EDIT: I have failed again. Read Dark's post.

Yes, it is possible to buy more than one bank chest. You would switch between them using /chest default <chestnamehere>

ty .can someone lock this for me