Got a customer asking for a detailed invoice after work has been paid
I gave them an invoice with a list of everything done and then a final price at the end.
I did some extra work at the end that is not part of the job originally that I added to the invoice, and when they asked to explain that number I broke it down (giving my hourly rate).
Now they want a detailed breakdown of the original invoice and are not letting it go, they are questioning how it can cost X when I was on site Y many hours. I just got another email saying they need it for themselves and their accountant, and say other trades have given them this.
They paid the original bill, and I even gave them a small refund after they kicked off initially. I thought after that were okay (I was still a little rattled) but with this new email they are demanding I send a detailed invoice.
How do I deal with this?
edit: job was a board change and putting in a new cooker circuit. ended up fixing some sockets, putting in bonding and moving some circuit.