An estimated value is not the money you will receive. A binding quote, the fees on that quote, and a confirmed payout are later, separate facts.
What can be sold
Only settled grams that are available can be reserved for a sale. Reserved gold is still yours until the disposal that the sale requires. Restricted gold cannot be sold while the restriction stands.
After you accept
Execution, settlement and payout do not happen in the same moment. The quote states the gross amount, the fee and the net amount before you accept. Live selling is closed. Sandbox quotes are illustrative and are not a tariff.
If the payout fails or is returned
A failed or returned payout restores the cash claim that belongs to that sale. It does not buy the gold back, and it does not create a new holding. The account should show the cash again and the gold as already disposed for that sale.
Payout destination
Payouts are to a beneficiary in the same name as the account. Changing that destination is an account change, not a note on a sale. See Account security.