When doing a return on debit why does EDC reports the wrong totals

I had a customer buy an item using a debit card, few days later she returned the item. so i recalled the sale for return and i refuded the amount to the debit. it showed the debit amount in ( ) which means it credited her account for that amount. but when ran the EDC report it did not show as a negative number so the balance was wrong. ?? but the bank shows the right amount deposited at end of the day . I called my reseller new west and they advised me of doing all the debit returns as credit card return not debit.so the EDC report would work properly. this is a glitch in the system or is there a fix on it. thanks