FNB pending transactions *****s my money!

I Thought i was alone but clearly not. Firstly i know exactly how much money i have in my account and how much i spend. For the past year i have been doing transactions with my cheque card. After the transaction goes off i get my sms like a normally do. The sms says the amount i used for my purchase has been reserved and my new running balance is R***x.00 amount. This i do not have an issue with and by monitoring this i know how much money should be left in my account and is normally correct. Then when i log into my internet banking i see that the purchases have been added under pending transactions. Whenever the merchants decide to do their banking that amount gets deducted from my account again after it has already been reserved and i have the sms showing so. This has forced me into a negative balance on many occasions and frustrates me to no end. When i called the call centre to find out what was going on i was told by the lady that i should learn how to work better with my money and that i should stop spending more then i have in my account. This is arrogant to say the least. I have no overdraft on this account and could no longer care about my FNB account at all after being a customer for the past 20 years. Can FNB stop *****ing from me and countless other people and rectify this? Not with another call centre agent ut with someone that can properly explain the problem and give back the money i have lost because of this.