I'm having the same exact issues. I've spent hours on the phone and online trying to get my visual voicemail back. I can't. Manually accessing my voicemail provides me incorrect time stamps which I've also had to explore to no avail.
My battery is near dead around lunch. I get anxiousby the end of the day and constantly have to think about recharging. I have chargers everywhere and 2 battery banks around just in case which is ridiculous. I haven't suddenly started using my phone differently to rationalize this and actually use it less than I did months ago.
So my phone is slow and glitchy, i don't even get notifications about voicemails, my visual voicemail doesn't work, my vm timestamp is wrong, my battery is down 15% with a half hour of use trying too fix my verizon issues, and this is hours of my life while I am already so stressed about so many issues in my life right now.
The only reliable solution to fixingthe voicemail issue that I've found is to change carriers. I'd like to stay with verizon, but this has been almost 2 weeks. I'm in the military--I can't have a phone that doesn't even function as one. I already have an iPad. I guess I'm giving it until Monday to fix itself and then I'm back to att.