Hi,
I understand your frustration. It can be difficult to deal with unlinked credit card transactions, especially when they are old.
There is no way to directly merge an unlinked credit card transaction with a customer. However, there are a few workarounds that you can use.
One option is to create a new invoice for the customer and include the amount of the unlinked transaction. You can then send the invoice to the customer and ask them to pay it. Once the customer has paid the invoice, you can manually link the payment to the unlinked transaction.
Another option is to create a journal entry to record the unlinked transaction as a debit to the customer's account and a credit to the sales account. You can then manually link the journal entry to the unlinked transaction.
If you are not comfortable with either of these options, you can consult with an accountant or financial advisor. They can help you to choose the best way to handle your unlinked credit card transactions.
