Go to your 'calling history' file. If you show the call as 'outgoing', it is YOU calling the default callback number to access / retrieve your voicemail messages. If you show the call as 'incoming', it is a number that is being spoofed by a hacker or robocaller computer. Don't sweat the 'outgoing' events and block the 'incoming' ones.
1-832-494-9000 is a House of Ill Repute. A new form of "doorknocking" they call potential clients offering pleasure. It's a Southwestern Bell landline.
I have been receiving calls from this number ever since I bought a new cell phone from AT&T. I never pick up because I am on a pay as you go plan. I have listed my number on the "don't call" list, which hasn't worked. Can I do anything more?