FNB bad client service

I called FNB call centre yesterday about a query on my account. I booked 2 plane tickets on expedia, and FNB reserved the funds on my account and deducted it from my account, and then the 2 plane tickets went off again in 2 payments (one for each ticket). I called my private banker numerous times yesterday, and no one could assist me in uplifting the pending amount. FNB has been sending me threatening sms's that will affect my credit score, and they said they will close my account. The staff was very unfriendly and very ***********. I don't know what to do, I cant use my bank card. No one is able to assist me. Please help.