When you log in to your Teammo account, your dashboard will always show upcoming matches first, not matches that occurred in the past.
However, if you need to pay for a match that occurred in the past (e.g. paying for it the day after), you can go to the Matches page, which is accessible in the menu:
All matches will be visible on this page. Find and select the game you want to pay for from this table. You will be taken to a payment screen to finalise your payment.
If you manage multiple teams, you will see all your team's matches listed on this page. You can filter by team name to see matches for a particular team.