Suntrust Bank ATM took money then went crazy now they do not want to give money back Smyrna, Tennessee

I deposited $400 in this ATM and the machine started going crazy, then it gave me back $20. I reported this to the bank and they gave me a provisional credit of the $380 after a lot of hair pulling. Then about a month later the bank took $80 back out saying the counted the machine and it was only $300 over so I called back again and they told me to put this in writing and fax it to them but it was nothing they could do because of what they counted. This is the second time this has happened to me with this company. Last time I lost $200. I have to use the ATM for deposits as my business closes the same time the bank does. I need a new bank ASAP.