MYOB AccountRight Using Old (CLOSED) Invoice Numbers

HI Team,

Today I had to delete an invoice and recreate it due to GST issues so I had to replicate the invoice by using the same invoice number but had to manually change it to reflect the invoice I was amending. And later on today I was putting through an Invoice sale, however I forgot to change the sequence to the most recently used number so I ended up processing the sale using an old invoice number so now there are 2 sales under invoice: 2009186 one CLOSED and one OPEN. I had already emailed the invoice to the customer! Can I just delete the invoice and recreate it under the next invoice number in the sequence or will I be required to credit the invoice? And if so how?

Thank you!