Hi @w.lestari! Unfortunately, it is not possible to deactivate the Onbeperkt Online Bundel . 
Since you can't use the new bundle I can give you a refund (prepaid credit) of your new bundel. Can you add your prepaid details to your profile? Please enter your name, phone number and SIM card number. 

I already do that. So how can you help me to refund of my bundel. Thanks

@w.lestari Great! I just checked the prepiad balance and I'm wondering: How did you activate this bundel? My system indicates that the bundle cost €0.00? It seems I have nothing to pay back. 

I do not really understand. but in the app it shows like this. I bought the unlimited internet bundle. and then 1 week later bought another 3gb internet bundle because my first bundle was too slow. but after i bought my second bundle it didn't work either. and the timing of the two bundles is still running.