Problem with Cash Account

Hi I made a mistake and set up an item with two entries - both for a cash value of £3.20 (£6.40 Total) coming from directors account and going into the cash account. The cash account shows as having £6.40 but when I try to add a payment for £6.40 it says that it will take over my agreed overdraft.

I have tried to void the original entry but it shows in the void section but when I select it and go to confirm it I get an error message saying that the item cannot be found.

Can anyone help me fix this?