I don't have a 10 digit customer number to link my internet subscription to my account

I have a KPN mobile subscription, and recently also got a KPN internet subscription. To link the inernet subscription into my account it asks for a 10 digit customer number which should be found in either my contract or my direct debit - but I do not yet have a direct debit, and the number is not in my contract.

Additionally, my connection at home doesn’t seem to be ready for me to connect the router I received to. I therefore need a technician to come over, but can’t book that unless I have the internet subscription linked in my account.