Hi,
I've been having the same issue with Swisscom for the past couple of months.
The connectiond drops multiple times per day at times, some times it comes back on its own after few minutes and some times i have to manually turn off/on my router. Very annoying since i have a couple of home servers im running to access from the outside world.
I ran some tests at home to make sure that its not my local network thats messing up by removing Switches, replacing Switches and so on with no go. Problem still presists..
When i called customer support they said they can see some irregularity in my vDSL line and will send a technician to check my line here at home next week.
But from your post, its not giving me much hope.
Im using a Zyxel P-870HN-51b which i do not recommend anyone to use.
It is the only modem Swisscom has that supports multiple static IP's and it hasnt been very helpful.
If the technician does make a difference, ill report back here and let you know.
Fingers crossed.
It would be nice if people with similar problems can report here to know if its just affecting some models/users/areas or its wider then that.