I Can't Delete an invoice I made by mistake. Really annoying!

Hi created an invoice instead of a quote by mistake, with zero costs in the item fields. Then after I created it and realised I made a mistake (i.e. I realised it was an invoice not a quote) I can't delete it. It shows up in the 'paid' invoice section and there't no 'delete' or 'void' options anywhere on the list view or when i click through into the invoice, or when I edit the invoice. This is infuriating.

Sean