I don't know exactly what time it will be released tomorrow morning. But historically, the phone line to book has opened at 7am. I wouldn't wait until 7am and I wouldn't call if you can book online. If you wait to call, you'll be on hold possibly for hours and behind thousands of callers. Also a long distance call to the US for most Cdns so pricey. If you absolutely have to call, check out skype. I've had luck in the past 10 years booking online before 6am. Usually, the offer opened to book on the website between 5:15am to 5:50am EST. I'll be checking online by 5:20am and then refreshing every few minutes. NB if you can't get in by 6am, try a different browser.
MDE is notorious for playing bad with almost every online browser. Consider firefox as well. Others have reported they had better luck getting online using incognito. Still others have had a laptop, ipad or other device charged and at hand in case they couldn't get through on their phone. I remember waking at 1am in the hayday of free dining fever and checking in here on the Boards and other platforms with other hopefuls. I don't get the sense this free dining drop is as coveted or even as known as those in the past. Good luck!