No response from these people, only threats

I have tried numerous times to correspond with these people via email so that I have proof. Instead they harrass me at work, where my boss is getting irritated. When I ask them to correspond via email please so that we sort this out, they never respond to my emails. They refuse to assist me with my query. Everytime they phone I have to explain the whole story to a different person, and I still get no resolve. I refuse to correspond with an uneducated person via phone. Contact me via email.