That is strange, you must have done some mistake while applying the code.
Can you please share admin access details as well as share where you added the code.
In addition to that, please clarify and confirm that you want AND relationship with all the custom field filters added - right?
*** Please make a FULL BACKUP of your database and website.***
I would also eventually need to request temporary access (WP-Admin and FTP) to your site. Preferably to a test site where the problem has been replicated if possible in order to be of better help and check if some configurations might need to be changed.
I have set the next reply to private which means only you and I have access to it.