I know you can put a stop to cold calling on your telephone from callers within the uk but how about the international ones? I've had a few recently and when I tried to hang up it wouldn't cut off, then I heard a ringing tone and then some american accent thanking me for responding to a competition!! I quickly hung up again and will no doubt get a charge but how do I stop them keep calling? I wouldn't generally answer but my friend has just gone on hols and thought it might be him phoning!
We too have had this problem. One thing we found helpful in some cases, was to be asked to be removed from their data base. At least for a while we have been free of such calls, although perhaps I shouldn't speak too soon!