I canceled my telephone contract with german Telekom cause there are obvious cheaper ways for me to use my telephone and save some money.
I already have my Internet connection from Kabel Deutschland cause they simply where a lot faster than Telekom offering Internet in my area some years ago.
I chose the package that they are offering for 30 Euros a month for internet and telephone flat (Festnetz).
We got our last regular Telekom invoice in September (18,02 Euros)
In Oktober we recieved another invoice about 5 Euro something for some calls they had forgotten in summer, whatever. After that we recieved another invoice for 4,91 Euro which we would have "PLUS" that would have been cleared with the next invoice.
i told them that I am no longer customer of Telekom and they should send me a check for deposit (Verrechnungsscheck) which they kindly did.
Here`s a picture of what I got in the mail today:

It simply shows me that I made the right decision ;)