She will come back the next day or so. No need to get upset about, and be sure to keep a eye on your tamagotchi when it's 10:30 AM, 3:00 PM, and/or 7:00 PM. If you have your sound on your tamagotchi will beep when the matchmaker come. Good Luck.
chances are they you pressed it right when she was leving. Stay with it alot becuse if you don`t the mackmaker will keep leaving(thats why people say it never comes)and your tama will be a oldtimer and machmaker will never come and you have to die.
I suggest to try setting the time to 10:29am then one minute later it will come up if your tama is old enough. ( It won't work if you set the time to 10:30am) Keep in mind that on V3s the matchmaker stays for about 15 minutes, but on V4 they stay for about 30 seconds. Hope I helped you. PM me with any questions that you might have.