A deposit that has not credited yet is almost always waiting on confirmations rather than lost.
Check the confirmations
The market credits after the network confirms the transaction. Bitcoin can take from minutes to hours depending on the fee you paid and current congestion. Monero is usually quick. Until the required confirmations land, the balance will not show.
An underpaid Bitcoin fee
If a Bitcoin deposit is stuck for hours, the usual cause is a fee too low for current congestion. The transaction is on the chain and will confirm eventually as the mempool clears. It is delayed, not lost.
Confirm the right address
Make sure you sent to the deposit address from the correct order. Awazon issues a fresh address per order, so sending to an old one is a common self-inflicted problem.
Still nothing
Once confirmations have clearly landed and the balance still does not show, contact market support through the on-site message system with the transaction details.