Hi there I had a number that was with Bt originally about 5/6 years ago we moved it to a mobile network to save on the call forwarding costs using a virtual landline after about 3 years we changed to a new provider and this number should of transferred with the mobile number to a new mobile network over 2 years ago.
the number had been working up until about a year ago, up till then we ware unaware the transfer had never worked and only figured it out when then the number had went dead.
we have tried Bt and the mobile networks over and over again since the early part of last year and was told hopefully the number would eventually fall back to Bt but up till now still have had no joy it is a business number which we have had for or 16 years any help would be great thank you
Assuming you are a bt customer then as business you need to post here as this is a residential forum
https://business.forums.bt.com/
As it is a bt business number there is nothing this residential forum can do to help
you will need to be a bt customer before you have any hope of getting number back
As @imjolly has said, if the number is owned by BT, then the only way to get it back, is to become a BT customer again.
If you open a BT Business phone account, you would initially be given a new number. Once it is active, you can ask for a renumber back to your original BT Business number, provided you are still at the same address, or an address which is served from the same physical exchange building.