There is a great option through Skyline Payment Systems, I can show you how it works and have about 70 clients using it.  It automates all of the backend processing so no entering of receive money or batching out the CC or ACH batch at the end of the day. It allows customers to pay with CC or ACH, you can pass along the fees, you can take a prepayment from a sales order, it sends automated past due reminders per whatever cadence you setup eliminating the need to send statements and it has a customer portal where the customers can see and pay all of their open invoices and see their payment history.  Reach out if interested.  [email protected]