Someone called saying they were from "visa/mastercard agency". Said they had detected unusual activity on my card and that they would reimburse and secure my account.
They asked what device I used and tried to get me to go to the app store to download "team viewer support". This would allow them to connect to and/or control my device - potentially allowing them to see account numbers/balance/passwords etc. Fortunately I could see this was a scam from a mile away. Don't get fooled by these people