Problems with a larger and very aggressive competitor

Hi some general advice would be much appreciated here basically what can be done about a larger and very aggressive competitor continually cold calling round your customers and telling them things about your company / service that are not true.

This has happened to a friend of mine and he is not so bothered about the aggressive calling but more about the call content. The competitor is using emails, although I guess / think these are not unsolicited more follow ups / replys to prospect enquiries. Their sales staff frequently seem to make up factually incorrect nonsense to get the sale.

My declared interest is that I used to work with the guys who started the company and they work really hard and offer a great service but are continuing to suffer this behaviour. Is it illegal?

I will post a link to some of the details and the competitor (is this the right thing to do?) I am obviously not looking for anything specific but are they heading down the wrong route posting the information publicly? what can and should they do? if anyone who specialises in this sort of thing wants to pm me their details and offers legal services please do so.

Here is a link to further information competitor is ekmpowershop.