Some of the organisations will help over the phone. I was speaking to my electricity company to change centre pay stuff only yesterday's nd they offered connection to a financial counsellor. So they are available all over the place. Definitely contact centrelink. Post office isn't an unforeseen expense so given it's come up and you weren't prepared for that expense, you may benefit from help kwim?

I'm not having a go at your organisation skills - just offering help to get you to a position where this stuff doesn't knock your budget around so much when it comes up