Why email or text somebody when somebody tries to login and fails?
If your security is stringent, including complex passwords, then perhaps it might be somebody who has legitimate access and has not typed in the correct password. As you will have applied a policy whereby multiple login attempts will be blocked, what is the problem you are trying to solve, if any?
your database accounts are assigned to "profile", you need to change the profile setting assigned to these accounts so the account is "LOCKED" after certain number of failed login attempts.
if you are trying to know if somebody is attempting a "brute force" attack with many attempts then you can monitor the audit entries in SYS.AUD$ table through scripting (not complex) also you can integrate your audit logs with other security products SIEM solutions that will handle such reporting.