Unlock my voicemail

I need help on unlocking my voicemail. I have been trying to do this on my own. It should not be this hard. If it is my phone and my voicemail I put in my correct password in steel was locked out months ago. Didn’t have time to finish up the work, but now I need to hear my voicemail because I have a very important message that was sent to me. Help me get into my voicemail today.