If you have an integration to a bookkeeping-system, the invoice statuses will change automatically when the payments are registered. In MATCHi you have to register payments actively by either doing it manually or by using a Bg-Max file from the bank. It is a list of your incoming Bank giro payments and the list can be imported to MATCHi and will update the payment statuses.
Via Bg-Max file: Extract the file from you bank and save it on the computer > go in to MATCHi under Administration > Invoicing > click the back "Register payments"-button > click "Browse" and choose the Bg-Max file > click "Next" > double check the payments and confirm. When the invoices are registered in your bookkeeping, you can mark them in the list > click Choose action > Change status > "Registered". That way you will get the "Not paid" status for unpaid invoices, the registered invoices cannot be edited.
Change payment status manually: Go to Administration > Invoicing > mark the invoice that should be updated > Choose action > Change status. When you mark an invoice as "Registered" (registered in your bookkeeping), it can't be edited anymore. If you register an invoice that has the status "Not registered" it will change to status "Not paid".