Adrey Low

Hi I'm a non UK Citizen and I live abroad. We owe a flat in Birmingham which we need to pay tax on. As a non citizen, I cannot file on-line which means I need to paper file. Unfortunately the SA100 cannot be downloaded which means I need the forms send to my address. I have recently moved which means I need to inform HMRC of the change in address. And because I don't have an online account I cannot change the address which brings me back to the same problem of not being able to get through to the helpline. This is hugely frustrating. Can you please advise on what I should do to get around the problem at hand?