I got call this morning about a free sim card

[LizzieC]

They said they were updating sim cards, and giving a discount on my charges. 

I got suspicious when they asked me to confirm my email address.

Was it right in thinking this was a scam?

[clivejo]

Did they ask you to "confirm" any other personal data? name? date of birth? or ask for a code they sent to your phone?

[Paddiewack · Accepted solution]

Highly likely! There’s no need to “update SIM cards” unless they develop a fault. My advice to you is to block the number and report it to Three and action fraud.