Credits to a Client Account do not show seperately once an invoice is paid, implying no credit

When a credit is added to a client account and an invoice is issued and that credit kicks in, once the invoice is paid, the paid amount becomes the total of the credit and the paid amount by the customer. To the customer there is no evidence that there was ever a credit. We can see this from a company perspective, but the client cannot. We continue to get emails asking why they were charged the full amount. The only way to show evidence this was not the case is via the receipt or a screenshot of our dashboard. This is not a good solution and credits should be communicated obviously per invoice. We have to handle this by adding notes and even then it's not sufficient.