Why was shipping charged when I offered it for free?

Topic summary

A new seller sent an invoice offering free shipping but the system automatically charged shipping when the buyer paid. They are seeking help to prevent this from happening in future transactions.

Key Issue:

  • Invoice was created without shipping charges included
  • System added shipping fees automatically upon payment receipt

Status: Question remains unanswered - the seller needs guidance on how to properly configure invoices to ensure free shipping is honored at checkout.

Summarized with AI on November 23. AI used: claude-sonnet-4-5-20250929.

New here, I just sent an invoice and I didn’t charge shipping on the detail since I offered free shipping, but when I received payment it automatically charged the shipping. How can I prevent that for next time?