DSL connection constantly going down

In the past few months my home DSL connection at 10117 (Berlin) has been a complete disaster.

It goes down for 2 or 3 minutes several times a day, mostly at night or weekends. Is extremely annoying and completely ruins any experience around using the internet. I can't even stream a movie on netflix without it going down and having to wait for the net to come back.

I tried to call the support line but as they don't speak german they just hang up on me and don't provide any support at all.

If you are having networks problems please acknowledge so and fix them. And please don't ask me to reboot the modem.