Re: I've issued a credit to a client. The client hasn't used the credit but has paid other invoic...
Welcome to the Community - thank you for your question!
To confirm, does the credit need to be applied against an invoice?
Could you please go to the cog wheel > account & settings > advanced and make sure under the automation section that automatically apply credits is turned off? Once you have done this, go into the invoice payment the credit has applied itself against, untick the credit and save. It should now remain open, so you apply it against the correct invoice.