Lost landline number (after 60 years).

[Dhsjhs]

I recently switched to virgin media and requested that our home phone number was kept during the switch to virgins digital voip home phone. However they seem to have lost my our old number and say it can not be retrieved. 
to try to sort this out is rang bt and said I am willing to take out a new landline contract to get my number back (do not care who the landline is with but the number is vital to my 85 year old mother and all relatives and her friends (who are also over 80). To give e out a new number will be next to impossible. 
I called BT and explained that I was willing to start a new landline contract to get the number back. The person I spoke to was superb. It came back and said the number is gone and can not be retrieved. 
one thing that amazed me is that when I plug the phone into the bt landline socket I get a dialing tone and when dialing 17070 it says line ok and gives me a local number that is not ours. Bt says this is impossible as the line does not exist anymore and no line is open to our property. 
can some help as I am at the end of my tether and my mother is distraught. 

[iniltous]

You are almost certainly out of luck , when your number was exported to VM ( and  a result of your BT service cessation and VM requesting the port of the number ) the Openreach ‘line’ is stopped and renumbered to a dummy number , that’s  the one read out when you dial 17070 , this allows the export if the original number but is also done with straightforward cessation as well .

Because the cessation was on the PSTN , that’s now defunct for new customers , which is what you would be if you rejoined BT , so BT telephony would  have to be Digital Voice , DV ( IP telephony via a ‘router’ ) and for whatever reason BT can’t or don’t retrieve ceased PSTN numbers , although a BT PSTN number migration to BT DV is the normal path for BT customers, once a number is ceased it’s a different story, and because the consumer isn’t a BT customer anymore, it seems impossible to retrieve the PSTN number as a new provision on DV , plus in this case the number is probably now allocated to VM and even though they aren’t delivering it to you , BT have exported it as requested, you would at a minimum get VM to cancel the porting request.

The responsibility is with Virgin to sort this out , the number is available for 30 days after cessation in part for  occasions like this when the importing company mess up .

Slightly irrelevant but what happens if you call the wanted number ? do you get an answer service, if so , from who , or do you get number unobtainable or a message saying the number called is no recognised ?, it may indicate the status of the number within BT and VM 

[brookheather]

Your old number should be quarantined and not allocated for at least 30 days - has it been more than 30 days since you switched?  If you are still with the 30 days you could look at moving it to a separate VOIP service - this would require an additional box for the VOIP connection which your existing phone would plug into.

[iniltous]

Although porting to a third party VoIP provider may seem a possibility, I’d suggest it may be problematic, who does the VoIP provider contact , BT doubtless would say it’s not our number anymore we ported it to VM , and VM would say it’s a BT number contact them , obviously it’s worth contacting a third party if other avenues fail , but it may be impossible to resolve via that route