never ceases to amaze me how many sellers don't 😐

I must agree with that and the worst offenders are Aussies and the Asian sellers.

I don't think I have ever had a problem with mail from the USA, Canada or the UK but well in excess of 50% of my Australian mail has no return address.  I can never understand why sellers and buyers want to keep their addresses and phone numbers a secret if they want to sell/buy on line.