Do I need a formal letter to the bank if I am trying to stop an ACH transaction from going through? And if so does anybody know where to find one? I've seen the letter for the actual PDL's but haven't been able to find one directed at the bank. I know there is a 3 day period before the transaction goes through that an ACH must be withdrawn per Federal Guidelines. I guess my worry here is that I go to the bank and talk with them, they say we'll stop it, then it still goes through.