Problems logging in

I have been unable to log into my personal tax account. When I try i get the message saying password is incorrect even though i know it is correct as regularly log in. I then tried to reset password and had the following message 'You cannot reset your password online Contact HMRC to get help.' I have contacted HMRC and they have said they will investigate and have given me a case reference but are not getting back to me. Its very frustrating as i would like to file my self assessment and check my corporation tax account, neither of which i can do. Has anyone else had this issue and how do you resolve it?

Hi DCollins44 Collins,
We are sorry you are having issues accessing your online account.
As you have already contacted the online helpdesk they will review and contact you.
If you need to chase up the case you can contact the online helpdesk:
Technical support with HMRC online services
Thank you. 

Struggling with exactly this. And no one will help....