Hello Atlas Sarah, thanks for posting on the Community page, if the payment on the banking page is lower than the amount on the open invoice, you would just need to change the payment amount next to the invoice when you match if off. If the difference is due to the 10.00 credit applied to the invoice, you will need to delete the receive payment that links the invoice and the credit note.

How do I go about this? I now have -£10.00 on the customers account, and it states unapplied. I tried to create a new invoice for the customer to just see if the £10.00 would be removed automatically but it doesn't. Very confused and seem to be getting more as time goes on. What have I done wrong.

I have managed to sort the problem out myself by watching someones video on Youtube which simplified the whole process and made it easier to understand. Sometimes just having simple instructions can really help those who don't come from an accounting mindset.

Hello Community users, we just wanted to pop in and add a little clarification to this thread. When you have a customer that has overpaid the invoice amount, it will credit the amount and deduct it off the next invoice you create if you have the automatically apply credits feature turned on(cog in top right- account and settings-advanced-automation-toggle on or off auto apply credits). You can turn it off if you prefer to manually select when the credit will be applied.
In the case it has already auto applied, and you do not want it to you would need to delete the receive payment or edit it unticking the credit which will show and then saving it.
We appreciate that it can become difficult to discern what is happening so we are here if you have an questions we can go into more detail.