premise: How to dispute a debit charge<br>Identify the charge. Look at your atm statement or debit card receipts. See if you can identify each withdrawal or purchase billed to your debit card.
hypothesis: It is not impossible to dispute a debit charge. 
reason: The point of the whole passage is how to dispute a debit charge. Therefore my statement saying it is NOT IMPOSSIBLE (double negative) to dispute it has to be correct. 