Self-install broadband didn’t arrive

I received the pre-agreement details for a broadband contract, but nothing was ever delivered (it has been over a week since the delivery date). I have since tried again, and received new pre-agreement documents stating it should arrive on Thursday. I would like to check the status of both of these as clearly I would only like one of them, and would like it to arrive this time. I tried calling 0345 454 1111 but the helpline requires an account number, which I do not have and seemingly cannot create. Would somebody please help with this, else I’ll have to take my business elsewhere.