Phone calls about reducing my monht;ly bill

[Felicity]

I have just had aphone call from a company claiming that they work on behalf of O2 but are not O2 and they are offering me a reduction in my monthly bill. They know my tariff and they know that my monthly device rental is ending. They know my address and me email. They have sent a confirmatory email from portalmailer@plan.com but I am reluctant to sign and snd it back without just checking that this really is legit. Any advice?

[Bambino]

@Felicity 

It's a well known scam
Block the number and report it free to 7726.
Don’t open any links or enter any information.
O2 advice here:

https://www.o2.co.uk/help/safety-and-security/phishing-and-smishing-advice
https://www.o2.co.uk/help/safety-and-security/unwanted-calls-and-messages
https://www.actionfraud.police.uk/

How to block a number:

https://www.samsung.com/us/support/answer/ANS00062352/

https://support.apple.com/en-us/HT201229

[MI5]

@Felicity 

Plan.com are a so called trusted partner of O2 but they only sell business accounts and tie you in to long term deals that you will find very difficult to get out of.

They are legit in so much as they operate with the backing of O2 but they aren't really a company that you want to get involved with.

https://www.plan.com/