Ali N.

Cold calling is the marketing process of approaching prospective customers or clients, typically via telephone, who were not expecting such an interaction. wikipedia.org

Customer service is the provision of service to customers before, during and after a purchase. wikipedia.org

A sale is the act of selling a product or service in return for money or other compensation. It is an act of completion of a commercial activity. 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

Email marketing is directly marketing a commercial message to a group of people using electronic mail email. wikipedia.org

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.

Customer support is a range of customer services to assist customers in making cost effective and correct use of a product. It includes assistance in planning, installation, training, trouble shooting, maintenance, upgrading, and disposal of a product. wikipedia.org

Chat technical support is a form of technical support delivered via online chat. Online chat refers to a kind of communication over the Internet that offers an real-time direct transmission of text-based messages from sender to receiver. wikipedia.org