Getting a useful answer out of amazon seller support chat

Keep a small sheet with each case ID, the date and what they told you. When an issue drags on for weeks, being able to say "case X on this date told me Y" in one message gets it taken seriously much faster than retelling the whole story every time.

One issue per case, and put the ASIN, order ID or shipment ID in the very first message. The first replies are mostly matched to templates, so a vague message gets a generic answer. If you get a copy-paste answer that doesn't fix it, reply on the same case and say clearly that it didn't fix it and why. Don't open a new case, because then the history is lost. Ask for it to be escalated or to be transferred to the right team. The phone callback option is often better than chat for anything involving account health.