I arrived in the USA yesterday on a 10 day trip and my mobile gave me the new voicemail alert today, but when I follow the advice given in FAQs on this site to try and access my voicemail, I just get a busy/engaged tone from the network. So I've tried both calling my own mobile number direct and using the 443 code (I didn't expect 443 to work but just tried in case). Calling my own mobile (I'm using my mobile to do so as I don't have access to another phone) I've tried both +44794.... and 0044794... and also connected to both AT&T and T-Mobile network. Same result in every case.
I did not set up a voicemail PIN before I left the UK (didn't know I had to) but this should still work. Voicemail from the UK works fine via the 443 number.
I actually need to access the voicemail ASAP as I'm expecting it's related to a medical issue!
Thanks for any suggestions!