Spear phishing is a targeted form of phishing scam in which cybercriminals send highly convincing emails to specific individuals within an organization. The emails often contain personal information or details that make them seem legitimate and trustworthy. The goal of spear phishing is to trick the recipients into clicking a malicious link or downloading an infected attachment, or to reveal confidential information or money to the attackers. In this case, the customers of the telecommunications firm received an email that pretended to be from the company, but was actually a fake. The email directed them to a spoofed website that asked for their personal information, which could be used for identity theft or fraud. This is a clear example of a spear phishing attack.
Reference:
What is Spear Phishing? Definition and Prevention | Fortinet
What is spear phishing? Examples, tactics, and techniques | CSO Online
Spear phishing - OxfordDictionaries