An inexperienced user tried to send bitcoins to the exchanger address, but mixed up the "commission" field and the "payment amount" field. So, in the "commission" field, he indicated 0.21, and in the "amount" field, 0.0001. As a result, the man transferred $9, having paid about $18,000 for this transaction. Such an error is possible in some cold wallets, where it is possible to specify the commission manually.
It is almost impossible to return money after such a transaction. Therefore, you should always carefully check each filled field before sending.
Of course, there is a ghostly opportunity to write to the miner who received that very gold commission with a request to return the funds. After all, miners are those people, or rather their equipment, that checks and confirms your transaction. But how to contact the necessary miner is a big question. And it is far from a fact that he will respond to your request and return the money.