If an order is missing, should i fill out a claim/ email to USPS or should the receipient of the order do it? I tried and got an error message.
What do you mean by missing? Does tracking say it was delivered but the buyer didn't receive it?
Tracking hasn’t been updated for long amount of time.
You should since you bought the label
As a business owner, you take full responsibility of the package until it arrives at your clients address. Even if you get errors, keep trying. Otherwise, it will appear that you don’t care about being a small business or your customers and just grab your cash and go.
Only the sender can launch an investigation with the postal service or Etsy labels. How long has it been? If it has been an unacceptable length of time, then you should offer your customer a full refund or replacement. It is then down to you to locate the parcel or claim from the insurance.