HARASSMENT

These people phone me at least three time a day work. Every time a different person and even though you tell them that you are not allowed to get private phone calls they persist on phoning. I offered my email address and was informed they cannot use that as they need to record the conversations. Now I ask you what is better than a recording EVERYTHING ON PAPER. The law stipulates that if you request them not to phone you at work they should comply. How do you get it through these peoples heads?