How do I set up voicemail on Galaxy S6?

[AC Question]

Transferred my phone number from an AT&T iPhone to an AT&T Samsung Galaxy S6 Active last night. Voicemail requires a password but I don't have one (never had to enter one on iPhone). I tried calling the AT&T number and they say I am not authorized because I changed out the SIM card (which they did at the store) and to try again later then I am cut off. I need voicemail today for work. Help!

 

[B. Diddy]

Welcome to Android Central! It's the same phone number, right? When you say you changed out the SIM card, do you mean you had to get a new card, or you simply swapped the card from the iPhone into the S6 Active? It doesn't make sense to me that they would say you're not authorized, assuming this is the same phone number and account as before, and assuming your account is in good standing with them.