New internetconnection isn't working yet and Wifi Manager cannot help me

I recently switched from Ziggo to KPN fiber. The Modem arrived yesterday and the installation via mijn KPN app didn`t work. Also Online vi"a a laptop the Wifi Manager doesn`t work. It gives error message : Jouw internetverbinding is nog niet klaar voor de Wifi Manager. Probeer het later opnieuw.

Already tried multiple times power off and on without any sucess. 

I called the support center and they explained how to install the modem directly wihtout the KPN app or Wifi Manager. However now I`m stuck with the WIFI Boosters that can not be installed without the Wifi Manager. 

I noticed from the forum that I also have an old KPN customer number (xxxx547) linked to my account. 

I can not delete it , it gives error message : “Omdat dit abonnement nog in behandeling is, kun je de gegevens nog niet aanpassen.”

To make it worse, KPN already called Ziggo and canceled my internet. My modem wifi doesn`t not reach my home office room. I need internet to work today. Please solve this problem.