Lost landland number after bereavement account name change

Hi,

My father recently passed away who had a virgin media account. I rang up on behalf of my mother to tell them about the bereavement and sort her on a new contract. 

After arranging a new contract and being  assured by the vm team that the landline number will be transfered, she was given a new landline number on the account. 

I rang up to ask them to transfer her back to her old number, but vm have said that it is not possible due to it being under different account names. 

Does anyone have any experience in successfully getting their old numbers back in a similar situation? It seems absolutely unfair to me that people who have suffered a bereavement are unable to keep their landline number. 

She is a 70 year old who relies on that number to talk to friends and family and our family has that number for 30 years. It is such a shame that only due to my dad's passing that the number has been taken away. This is really something she doesn't need right now and virgin media are being so unhelpful, just keep saying the same line over again that they can't transfer numbers with different account names with very little sympathy. Surely there is something vm can do to keep a number, it seems ridiculous that every time someone passes away their partner has to have a new number. Any help on this would be appreciated