I recently transferred to Now TV for their phone & broadband package. It didn't go to well as, unbeknown to me, Now changed my landline number after thirty+ years. On Discovering this I complained to Now who did nothing and suggested BT as my only option. I have now rejoined BT and was hoping that something could now be done in so far as recovering my old number.
Not much you can do for a while, when the BT service is up and running , if you post again, hopefully a BT Mod will pick this up then and ask you to contact them, then they should be able to process the renumber order to get you back with the original number , but not much can be done before BT are your supplier, presumably that will be the 28th