Sky email account can’t access

[Janine1820]

So on Thursday 10th august AM BSTy dads sky email account that he has actively used for 20+ years was working. Every day he logged in via the sky site with his email and password then accessed mail. 
On Thursday afternoon it asked for his password, he entered it and it said it was incorrect. He clicked forgotten password he has recovery email. He entered his last name and first street (written down so he knows) and it doesn't recognise them either. 
Sky can't find the account. He was never an account holder, my mam was 20 years ago but they can't fine her either and his was setup as an additional email account. 

He has lost everything important insurance docs etc.

Can anything be done? Letter of complaint? Subject access request? Someone who can roll back his account t to Thursday am if it has been hacked? Confirmation if tech support have accidentally deleted this as they haven't got the correct checks in place? 

[Janine1820]

My mam managed to speak to the Identity Management team

and they don't have records for either of them even though my mam's account is still working and can log in onto the main sky account!! 

[jayach]

Can you Dad log in here with his credentials: https://www.sky.com/myaccount/my-details ?

Has he possibly replied to an email recently asking him to update/verify/confirm etc his email address? If so he may have given his details to scammers.

[Janine1820]

@jayach it doesn't work. Sky have no record of my mam or dads account on their systems! My mam can still log in here. He's never been scammed as he's really careful doesn't save anything always goes through main link etc. I think they've deleted his account as it was a secondary and they don't seem to have the main account either although that is working. 

[jayach]

Just want does it say when he tries to log in on the link?

[Janine1820]

@jayach 'your password is incorrect please try and or use the link below'

we then click 'forgotten your password' enter the username click next and it asks security questions (no option to email as no recovery email set) then when we enter them the message is '

• Sorry, we did not recognise either your last name or the answer to your security question