Just 'cause you're cleaning out your garage on Craigslist or you've agreed to meet that new guy/gal for coffee doesn't necessarily mean that you want to get phone calls from them for the rest of your life. In the World of Email, there are services that will provide you with throwaway email addresses–an email address you can use once, or just a few times, and then it goes away. You aren't giving up your privacy and security just so you can get rid of that old sweater or exercise bike.
RingShuffle is an app you can download onto your iPhone. Like that disposable email address, RingShuffle lets you create a throwaway telephone number. Create a new number and by default it goes away after seven days, although you can dial it up or down to change that life expectancy. When your customer (stalker?) calls your temporary number, it rings through to your phone, but without disclosing what your real number is. You get the job done, but without establishing a long-term relationship to solve a short-term problem.