Unknown & Citigroup used

Victim Location 46304

Type of a scam Tech Support

Inundated with computer scam calls (647-556-7323 Canada; 213-457-4056 California; 201-374-8004 New Jersey). Caller ID stated ‘Anonymous’ or ‘Restricted’. This week I received a computer scam call with caller ID indicating ‘Citigroup’ (212-723-8154). After hanging up, I called # and recording stated ‘This Citi number is not in use." On 11-7-15 I called Citi bank and advised their name and former # were being used in scam. Apparently scammers can now use legitimate company names and former numbers in caller ID. How is this possible? I know they were trying to obtain personal/financial information because up until 11-7-15, I had no computer.