PaySuper from Electronic Clearing Account

We're attempting to do our first run of PaySuper from MYOB and have obviously misunderstood how the process works. When selecting "Pay From Account" We have put it to the Electronic Clearing House thinking we need to pay it form the bank but it isn't coming up in the file when we go there. When we went in to reverse the transaction it is saying that the funds may still be withdrawn from your account. Essentially we want to know if we reverse it if its going to cause any issues to fix it so it comes from the correct account, also if we need to do anything after we have authorised it from that account.