A payment is delivered once it has 10 confirmations on Zcash. Blocks are about 75 seconds apart, so that is roughly 12 minutes from the moment your wallet broadcasts.
If it has been longer than that, one of two things happened.
The payment is still confirming. Open the order again. If it shows as pending, nothing is wrong and nothing is lost.
The payment arrived after the order closed. An order is held for a limited time. If that window lapsed and the item sold to someone else, or the seller cancelled the listing, your payment is recorded but cannot be delivered. It is not lost. It is parked, and it is refundable.
To sort it out, send us the transaction id. Your wallet shows it in its transaction history. On a shielded transaction that id reveals neither the amount nor the other party, so it is safe to paste into this chat.
We look it up, tell you exactly what the system recorded, and arrange the refund or the delivery.