cannot delete db table
First have a look at the InnoDB Architecture (from Percona CTO Vadim Tkachenko) 



Your problem is very simple. You have a broken data dictionary entry. Inside the system tablespace file ibdata1 is a list of tablespace ids.

There is an entry for appointments.business_users. Deleting the .frm and .ibd of appointments.business_users does not remove its tablespace id from the data dictionary. You need to remove that entry from the data dictionary.

The reason you are getting the error still ? Although you can the CREATE TABLE and generated the .frm and .ibd file, the tablespace id in the .ibd file does not match the original tablespace id in the data dictionary.

Here are some old posts on how to repair it in place


From @akuzminsky : InnoDB issue after power outage a few weeks ago - no backup
From @DerekDowney : ERROR Cannot find or open table?
From me : restore table from .frm and .ibd file?


If the database isn't too big, you could do the following:


mysqldump everything EXCEPT appointments.business_users
drop all databases (except mysql schema)
shutdown mysql
delete ibdata1
start mysql (recreated ibdata1)
reload the mysqldump
manually run the CREATE TABLE command for appointments.business_users


Either way, you have some homework to do.