Which red flags should stop me from placing a lingerie order?

Five that recur. A first reply that answers price but ignores the construction questions. Refusal to show the cutting room or the pattern room. A quote with no validity period. Unwillingness to accept an inspection clause with a stated AQL level. And any request to pay into a personal account.

None of these is proof of fraud on its own. Together they describe a supplier who cannot show you how the garment will be made, which is the only thing you are actually buying.