MISLED & **** TO BY FNB

When I swipe my debit card FNB sends me a notification that the funds are being reserved for that purchase but when the merchant banks the transaction I find out that FNB **** to me that the funds were reserved and FNB then charges me an excess fee because my account is now overdrawn as they did not reserve the transaction although FNB notified me they did which results in my account being overdrawn when the merchant actually banks it then FNB wacks me with further excess charges after lying to me that they have reserved pending transactions. I am very disappointed in this low and *****ed manner that FNB, one of SA's leading banks operate. Please refund me for the excess charges as this costing me everytime FNB misleads me