FNB *****s money

On the 16th and 19th of May, R110 was debited on both days. Please refund me these amounts as I can not see that the bank charges are so high, if that is the case, I will gladly change banks. However FNB allowed my account to go on a negative and this charges me R110.00 for each transaction that they let through. No one called me about this, I never consented to this facility. I then called the contact centre and the consultant told me he will log it and investigate. I told him, why will I make transactions if I do not have money in the account? I want both the R110.00 that have been deducted on my account to be refunded as soon as possible. FNB is *****ing money. On many occasions I will buy stuff and days afterwards it will get deducted from my account. Please refund ASAP!