Suntrust Bank, Manipulating Payment of Transactions Savannah Georgia

I live in Ocala Florida and have experienced the same treatment with Suntrust Bank. They claim that they pay the largest transaction first, even if the lessor transactions have already been processed and there is a final amount was available. they say they pay the largest amount because that they are usually mortgage or car payments, etc. I ask them why I don't have a choice. I told them that I thought it was illegal change what has already been processed and creating negative amounts in order to add NSF charges. They said it was policy, and that was that. I made a mistake and processed a check 1 day to early, after I had already processed my original transactions. At midnight the check was deposited to cover the last check, but by then, they had already manipulated the previous checks. I will be changing banks.