i had the same, the call came through from 08000158180 (0800 158 180) and they told me to call 08003891652 (0800 389 1652). i didnt trust them

i then found out that barclays fraud number is 01604 254 050

after all, it turns out that it WAS a real call from barclays. but they did praise me for being diligent.

Even so, never trust people who call you! always call them back on a number that you find out, not neccesarily a number they give you.