Hi Victoria,
Method picks up the invoice numbering pattern from QuickBooks. Did anyone create an invoice with '- correcti' at the end of it? To fix this you can create an invoice with a proper number in QB(minus the '-correcti') and do a Full Sync with Method. That should rectify the issue.
-Michael
Michael Melo
Product Manager
Method Integration Inc.
Website: http://www.method.me
LinkedIn: http://www.linkedin.com/in/MichaelMelo