Lead generation, or lead gen is a marketing tool used, particularly in internet marketing, to generate consumer interest or inquiry into products or services of a business. wikipedia.org

Telemarketing (sometimes known as inside sales, or telesales in the UK and Ireland) is a method of direct marketing in which a salesperson solicits prospective customers to buy products or services, either over the phone or through a subsequent face to face or Web conferencing appointment

Phone technical support refers to a range of services by which enterprises provide assistance to users of technology products such as mobile phones, televisions, computers, software products or other electronic or mechanical goods via telephone.