I'm also having this issue. We use optus for our work phones and the bill comes in the mail. Trying to switch over to email bills as we are now all working remotely but I can't log into My Account to change it over and no one wants to deal with non-covid issues! So I guess we just won't pay the bill?! It would be great if they had someone doing customer service for regular enquiries - some of us have to be business as usual unfortunately.