Is debt collection intimidation illegal?

It is illegal to use intimidation. One of the following acts shall be detained for not more than five days or fined not more than five hundred yuan; If the circumstances are serious, he shall be detained for not less than five days but not more than ten days, and may also be fined not more than 500 yuan: (1) writing threatening letters or threatening the personal safety of others by other means; (2) sending obscene, insulting, threatening or other information for many times, which interferes with the normal life of others.