The functionality of this has been intermittent for the last 5 months for us.  On a PC, sometimes when we go into the customer profile, there is a place to input the customers payment (credit card or bank account) information, but often it is not there.  Even when we have customer's information already saved, it does not show up to add/edit the payment method.  This is also an issue on sales documents.  If we attempt to collect a payment from a customer with a saved credit card on a "sales receipt" or "receive payment", the credit card information and check box to process the card do not appear.