meter reading when switched address

hi I have just moved house, I was already with bulb, told them about the moved and added the new address. had an email asking for a meter reading for the new house, click on the link that takes you to your account to submit a reading, but it doesn’t let me. just shows me the steps of moving house and says finalising the bill.
any ideas? I don’t want to end up being shut off, and there is no way of ringing anyone.