Treat duplicate payment as a separate acceptance item in the first trial order. Agree in advance on the required account verification, payment terms, bank receipts, and milestone evidence, then have the person in procurement, logistics, or after-sales who will actually use the materials review them. If confirmation is only verbal at the sales level, funds may still be exposed before verifiable delivery progress. Base later order expansion on this record and on suspending and re-verifying whenever the account or entity changes.
For internal approval preparation, see How Do I Check If a Chinese Vehicle Exporter Has an Export License?.