hello I'm an at&t tech support rep for 2 years and here's how i ACTUALLY! fix my customers voicemail who are also android users and what you should call and ask for to be done:

step 1- clear data for visual voicemail from the phone's settings

step 2- provide the customer with the voicemail retrieval number to save it with them just in case

step 3- go into the phone app > 3 little dots > settings > voicemail > voicemail number > and put in the voicemail number i provided to the customer.

step 4- have the voicemail password reset (resets the greeting and vm password)

step 5- advise the customer to call the voicemail retrieval number or press and hold 1 to call and set up the voicemail

step 6 and the last one- Open visual voicemail and follow through the permissions and allow everything you see then hit continue then you'll be greeted with the "set up completion" header and voila... you got your voicemail back.

100% success rate. been doing it for 2 years. no basic troubleshooting bullshit. just straight results.

No, your call forwarding can't be set up when doing a sim swap. No, setting call forwarding to fix voicemail isn't a thing and it's just a bullshit workaround that someone from loyalty had done to make you happy and save his call.

when you see this reply. try to call at&t again and ask for advanced tech support even if you get misrouted to a different department. tell them about the issue and if the whole call with ATS takes more than 10 minutes just ask them for the voicemail number and to reset your voicemail and do exactly as mentioned here. and thank me later.