One email is enough to start. The four questions below are what I will ask anyway, so answering them now saves a round trip.
Email: [email protected]
Already placed the order and something is wrong?
Put URGENT in the subject line. Mid-production intervention, defect documentation, or supervised rework — from $399. These are answered first, before new enquiries.
A reply within one business day (China time, UTC+8), with one of three answers:
No newsletter, no sequence of follow-up emails.
If you have not calculated the landed cost yet, do that first — it takes two minutes and it answers a question that no conversation can.