Philippe,
thank you for your e-mail and apologies for such a belated reply.
Your message touches on a variety of subjects, so I'm going to answer them very briefly, hoping that other people might also want to get involved at some point. I'm afraid that you might have confused some things and mentioned subjects that are outside of our (mine or Guillaume's) control.
Firstly, we have never used any bots to notify translators about the issue being finished (and frozen); there are too many people subscribed to translation notifications on Meta, and Tech News isn't (yet) important enough to contact them all on their talk pages. Moreover, issue #29 was frozen on Saturday, and my last e-mail about it was sent that day; I don't know what notification you received on Monday but it certainly did not come from me or Guillaume.
Secondly, e-mail notifications are one of the things that lie outside of our control. I am aware that the Wikimedia mailing system can deliver some notifications late, but there shouldn't be any problems with this mailing list; I at least receive all messages almost immediately, even though I'm using a private e-mail provider. Can you clarify what you have in mind? Are these problems about e-mails coming from <wiki@wikimedia.org> or from this mailing list (<translators-l@lists.wikimedia.org>)?