Threats and harassments calls

Not a single day that goes by when I do not get Threats and harassments calls from this company. I am so sick and tired of these people harassing me. I suffer from anxiety and depression. There were so many times where I had to switch my phone off just to avoid calls from this company and then I missed important calls either from my doctor or son school. Can someone please assist me as I tried so many times to block them but they keep calling from different numbers, this company will really be the death of me because I can not handle this no more.