Just switch to 1und1 with good peering (:
Their service is good on a technical level but they have the most aggressive and obnoxious sales reps. They scammed me twice with open lies on the phone (probably abusing also the fact that german is not my mother tongue) and had to fight for ages with their customer service later to get the issue resolved.
If you wanna go with them, buy on their website and hang up if anyone from 1und1 ever calls. They are official 1und1 reps and they will prove it you yet behave like scammers.
DT called me on phone over and over again, so much that I had to block them on my FritzBox. Several times they even knocked at my door.