Why was I charged a shipping adjustment?

Carriers weigh and measure packages in transit. When one comes back heavier or larger than the label declared, the postage difference is billed to you, plus a service fee — larger on large corrections.

The charge goes to your backup card. If there is no card, or it declines, it is deducted from your next payout instead. Either way you are notified, with the order it belongs to.

It never comes up when the declared numbers are real. Weigh the packed box, measure it, enter exactly that.