Think about it: you see your internet connection dying as proof when they could have just as easily booted you from the conference call raising much less suspicion. I see it as proof of the opposite, they had a far easier and more direct means at their disposal to achieve the effect you say they desired. So I really do not believe that it was anything other than bad timing, all that it would take for this to happen is for your provider to reset a router somewhere.

My residential connection here is pretty good, even so it goes up and down at least once every week or so whenever some firmware update is pushed to the router.