[m_gloeckl]

You can file a complaint with the "Federal ministry for digital transformation" (formed this year). It does actually work, but it's a lengthy process.

I did force my cell phone carrier to grant me proper 4G speeds last year, after spending many hours with their help line and ultimately complaining to the (then) ministry of transportation and digital infrastructure.

[afeuerstein]

Can you elaborate on what was wrong with your cellular connection?

[m_gloeckl]

My plan advertises "up to 50 Mbit/s" on a 4G connection. I was getting less than 1 Mbit/s a lot of the time. Websites and videos would not load properly.

I downloaded the app of the german ministry that allows you to take speed tests and file a complaint. After multiple weeks of measuring connection speeds on the cellular network, I was able to file a complaint.