birb’s method using classified ads will get you finding pages of numbers and sites in just a few seconds. however, be sure to check the numbers! there are some people posting legit numbers, so always check if it matches with a real tech support number.
here are the sites where you can get scam numbers (use the exact link):
https://www.locanto.com/q/?query=tech+support - Locanto is a popular classified ad site that is also mildly popular with scammers!
http://www.kedna.com/index.php?a=19&b%5Bsearch_text%5D=tech+support+number&c=234&b%5Bsearch_by_field%5D=all_fields&search_location%5B0%5D=0&b%5Bsubcategories_also%5D=1 - Kedna is a classified ad site popular with scammers. I'm not sure of its popularity with actual people, though.
http://www.adlandpro.com/ads/search/Services_153__in_unitedstates.aspx?kw=tech+support+number#.XB1ojFxKhhE - AdLandPro is a classified ad site mildly popular with scammers.
http://www.kugli.com/Services/search/tech_support_number/ - Kugli is a classified ad site mildly popular with scammers.
This site list will be updated periodically.