USDT TRC20 Deposit Not Credited on MEXC
A MEXC deposit that hasn't appeared usually falls into one of two buckets: still confirming on-chain, or confirmed and waiting on MEXC's internal process.
Check TronScan first
Search your transaction hash on TronScan. A SUCCESS status to MEXC's correct deposit address means the network-side transfer is complete, and any remaining wait is on MEXC's crediting process.
Confirm the deposit address was for TRC20
Make sure the address was generated specifically for the TRC20 network in your MEXC account — check this before assuming there's a deeper problem.
Contacting support
If the on-chain status is confirmed and the wait has gone well beyond a few minutes, reach out to MEXC support with the transaction hash as your reference point.