USPS has raised their rates. Senders be advised.

You are lucky you are still getting 'service'. USPS has suspended air mail to many countries because of covid [ lack of planes in the air I guess ], including Australia.
Didn't bother to inform the sender or the receiver. Been waiting 5 weeks now from parts from Tenn. Tracking # just says 'in transit'. Could be coming by canoe for all that tells you.
Not the USPS doing that, it's Australia restricting it.
Don't know what they're telling you, but USPS was accepting parcels to Australia, they got there and were turned around.
USPS stopped after they were forced to return and refund postage to Australia.
But I want to stress, it's 100% not the USPS! They can ship worldwide with the exception of Australia, what's that tell you.