Unauthorized debit

<p>I'm in Brazil and I woke up to an email with a debit deduction by one Ttms PLTNM116891, I have no way of informing the bank to reverse this amount as I cannot call the customer number because although I'm roaming, the costs for the call will exceed the amount I'm querying. Is there an email for reporting this kind of transactions such that it can be reversed?</p>