credit history wrongfully wiped

My brother and I have very similar names, they only differ by one letter and we live at the same address. Recently he has been opening a lot of credit cards and they have wrongfully hit MY personal credit score and report instead of his. We contacted all the agencies and sent formal letters and proof of identity to clear the issue. Now it has happened a second time and this time they WIPED MY CREDIT HISTORY COMPLETELY. I can't even get approved for an apartment lease right now and I make well over 100k and had an 800+ credit score. How do I move forward? Do I need to take legal action?