Visual Voice Mail

My Visual Voice Mail stopped working a few months ago.  Still shows app and can still check and receive voice mails; however, no longer notifies me that there is a message. I just have to check periodically but by holding down "1".  When I go in and hit refresh, I get Error code 999.  I have also gotten that my voice mail was locked due to too many attempts.  I went into to change passcode per saw the previous information about that.  It gives me a "Temporary system error occurred, please try after some time".  Have tried numerous times.  I have application 17.1.00.15.  I have a S21 Ultra phone.  Also got message "user is blocked".  How do I unlock?  help please. 

Thanks,