I wish I knew why this happens. I had the same problem with my Music Star, the matchmaker NEVER came and my tama ended up growing old and dying...something that hasn't happened since owning one of the oringinal Tama's since I kept continuing due to the mating process in these new ones.
I always have my Tama's sound on and out where I can hear it beeping, when I have to go out I either leave it at home on pause or keep round the clock attention to it if I take it with me. So I couldn't have missed him.
I posted the same question you have many months ago, "where is the matchmaker?"
Someone mentioned it might be one of the glitches in the Music Star, I'm hoping that isn't the case.
This is why even now I'm worried since I restarted my Music Star to try again. If the same thing happens again I'm going to be forced to raise my Music Star and my V5 so that it has a mate.
I hope the matchmaker comes for your Tama. If it doesn't you might have to resort to what I'm planning.