A recent curve ball on this gateway setup - we have noticed a rapid decline in the number of transactions coming in from the site, which used to be several per day. On working with the bank account owner and his eprocessingnetwork account rep (they are indeed very helpful and friendly on the phone), we did see that he had no activity for several days and then only 1 or 2 orders trickle in. Another developer assisting with this project could not get his many test orders to go through with a valid card, but my test orders go through ok. Then a new customer placed a successful order on the website yesterday. However, on logging into the "Orders" area of ZenCart, I see several new "customers" (people who signed up) but no orders from those people. This leads me to believe that people are trying to order and not getting past the last step.

Investigation continues.