Terminate my DSL contract

It is super frustrating to call O2 hotline. Waiting few times more than 30 mins each time for waiting english speaking support.

Moving option in website isn't working. Going shop, the sales reps asked me to call hotline.

Now I just want to cancel / terminate my contract.

It is asking to call some service center again - of course German only.

Can anyone help me here to get a proper termination of my contract? Kindennummber: DE09392111

Thanks!