How do I cancel my internet contract with Telekom since moving into an apartment which has already an internet connection? According to German Law , since December 2021,  "if you move into an apartment where someone already lives and a telecommunications contract is already in place… you can terminate the contract before the end of the contract term to move out." 

I have attempted to contact Telekom through their customer service but it's almost impossible to make progress there - particularly as a non-native german speaker. I have documents to prove the fact that I live in a new apartment (Anmeldung) with existing internet (internet bills) which I can provide to the relevant persons.

Would appreciate some help with this - many thanks!
Alex