I never have any problems. I get a lot of missed calls but the serious people then ring back a few hours later. If they ring you listen and chat about it. If you get an email don't feel too lucky. One thing that shouldn't happen often is people contacting you from interstate nevermind overseas. I like it because it's free and there is no real classifieds in the local papers in my state so this helps it out and I get more serious responses and the site is supposed to split you up into groups/regions so that local people see your add first!
