FNB BAD PENDING SYSTEM

FNB is ***, had an available balance of 600 and made a purchase of 398. Next thing i know i am charged bank charges and my balance is on -98 ..I deposit 350 and it takes 190 and i am left with 160. How i don't know . Even their pending system transaction being put to reserve is a lie . Because the balance reduces and it further reduces when they move the amount from pending . and why they are the ONLY bank that has Pending transactions. They Must not lie and say the merchant system that is used is not the same .. because it should be real-time like any other bank and transaction. When I do a recon it does not balance. why can't they fix their problem? first, it was money and card and now this . and their customer services that never answers the phone including complaints department. If YOU WANT TO KEEP YOUR CUSTOMERS DO THE RIGHT THING AND STOP THIS NONSENSE.