What can you do if your Internet connection is too slow or down?

The broadband measurement desktop app needed for this was developed by zafaco GmbH on behalf of the Federal Network Agency.

Advertising promises made for an Internet connection are often a world apart from the actual speeds. In some cases, you can reduce your monthly payment or even terminate your contract without notice. The sample letter generator provided by Verbraucherzentrale Nordrhein-Westfalen e.V. (Consumer Organisation of North Rhine-Westphalia) can help you here.

You can find more information on the subject here.