curl --request POST \
  --url https://api.{your-broker}.slate-labs.com/transactions/{tx_id}/chargeback \
  --header 'Content-Type: application/json' \
  --data '
{
  "reason": "<string>"
}
'

{
  "chargeback_id": "<string>",
  "original_transaction_id": "<string>",
  "amount": 123,
  "balance_after": 123,
  "account_frozen": true
}