Any successful USD wire transfer from another country?

Hi. I have read a lot of posts about wealthsimple locking accounts on cheque deposits or wire transfers of huge amount. Has anyone ever had a successful transfer? How can I decrease the chance of this happening to me? Planning to move around 23k usd to chequing and transferring it to non registered. Also, why do USD accounts have letters on the account number? My sending institution does not accept letters in the account number field.