I usually tried to place the call more than once, only to hear the same recorded voice tell me the number wasn't accessible from my area code. As a prospect, this is very frustrating. As an advertiser, it's quite costly in terms of lost sales. The easy solution is to give your audience alternate means of contacting you. You never know from where in the world a response may come.
Libraries everywhere are one source of international newspapers, trade journals and magazines.
This is particularly true with on-line marketing, but it also applies to any major publication you may contact. Instead, such claims trigger doubt, disbelief and inaction. Everyone has heard it all before and many have been fooled, at least once, into replying, only to be deeply disappointed at some point. Anyone can make a general claim, but you can enjoy a far greater rate of response by being specific, with actual numbers that also appear to be more realistic. In no way am I implying that you should manipulate the numbers so that your statement of claim seems very real to your prospect.