An order moves through a fixed set of stages. You can see the current stage on the order at any time.
1. Request
You send a request from a listing, giving the volume you want and your delivery terms. This is not yet a purchase and nothing is charged.
2. Quote
If anything on the order still needs pricing, the seller sends you a quote. You can accept it, or reply and negotiate. While a quote is open the clock on your order is paused, so you are not penalised for taking time to answer.
An order with an unpriced line cannot be paid. This is intentional: paying first would leave that line stuck with no way to price it.
3. Payment
Once everything is priced, pay the invoice by bank transfer. See "How payment works" for the detail.
4. Fulfilment
The seller prepares and ships the order under the agreed delivery terms. Full contact details are shared between the two sides at this point.
5. Completion
When the order is complete the seller is paid out. The order stays in your history.
If something goes wrong
Open the order and use the message thread attached to it. That conversation is linked to the order, so whoever picks it up can see exactly what you are referring to.