Suspicious phone calls, Scammer?

[SimingGE]

Someone said he is from O2 and can provide me with a new cheaper contract to transfer my VM broadband to O2, and the number is 02045799973. I hung up the first time, but he kept calling for a few days. I called customer service to ask, but they said they were unsure if VM was transferring my broadband to O2. Anyone know its a sammer or something for real.

[MI5 · Accepted solution]

@SimingGE 

It's a well known scam.
Block the number and do not follow any links.
Forward the scam text or number to 7726 - It's free.
Other ways to report here including Action Fraud website
https://www.o2.co.uk/help/safety-and-security/phishing-and-smishing-advice
How to block a number:
https://www.samsung.com/us/support/answer/ANS00062352/
https://support.apple.com/en-us/HT201229
https://community.o2.co.uk/t5/Welcome-News/Scam-Alert-Vishing-Smishing-amp-Phishing-Megaguide/td-p/1...