That's right, the addresses of the M3U are only usable at a Telekom port with an active IPTV conctract!
But an the other side, since some time the Deutsche Telekom offers IPTV independently of an running DSL or telephone contract. But atm this is only usable with the dedicated apps on Android /iOS or via browser, with another way of verification and encryption!
Here in Germany all private (RTL Group, Pro7 Sat1 Group, etc.) HD channels are encrypted, so it isn't possible to use free stream addresses! There are workarounds with an active Zattoo or Waipu subscription, you only have to search here in the forum!