If it all happened today or yesterday it will be because the number you have and your location for it aren't yet updated on the relevant BT databases. There are about three I think.
Is it the same number as you had on Sky, or a new one. Same applies whichever, just probably a different bit of the updating loop to jump through.
Try a couple of times a day for a few days. Two to three days seems to be the norm.
I assume your Sky LLU broadband is still working?