MBD Harassment

Constant harassment from MBD for years now. I have tried numerous methods of tellings them that I am not the person they are looking for. Constant phone calls and messages, unbelievably annoying. I am at the point where I want to record conversations with them to take legal action against them for harassment. Seriously, what does a person have to do to prove that I am not the person who you are looking for? And why is there no response to emails asking to resolve this in a friendly matter?