Sounds like you must have been out of minutes or getting very close. So after topping up and hitting Pay Now, you then needed to hit Restart My Month, and this would have then reset your minutes back to the full amount and kept your due date the same, since you would be restarting your month on 7-4.
Now, you should still be fine to go ahead and hit Restart My Month today, which will then give you your new allotment of minutes, but will also change your next due date to 8-5, IF you do it today. The next time you are running low or are out of minutes and need a fresh supply, just remember to restart your month (after paying) and you should be good to go. If you are doing this from the website, just refresh the page and you should be able to see the change. Also, the date you restart your month becomes your due date. Hope this helps.