I raised an issue via the app when some unknown transactions started appearing on the app, didn’t lose any money but it was obvious someone was trying to use my card online. Monzo responded via the app and I have a new card on the way, but strangely and almost immediatyely I then started receiving calls (No Caller ID) from individuals claiming to be from Monzo and seeming clued up on my issues. The callers didn’t ask any security questions and actually starting asking for card details from other banks claiming they could check for fraudulent activity on those, obviously I didn’t share that. I hadn’t raised this issue with any one else but Monzo and the way the calls started immediately after I raised the issue with Monzo is concerning. Has anyone else experienced anything similar?
The only people who would be clued-up on your issues are you, Monzo, and the scammers themselves. The latter may be trying to submit false transactions which are now failing due to your card being blocked, hence why they know you have blocked and ordered a replacement.
Monzo have a system (Settings > Privacy & Security) to identify when they are on the phone to you, so if you get any future calls where they claim to be Monzo, I’d be checking that. Monzo would definitely not call you out of the blue, from what I’ve read.
These will be the scammers who made the unknown transactions, that’s how they know about them. That they started calling after you contacted Monzo is likely little more than coincidence - they probably would have contacted you when they did whatever you would’ve done.
(It may be worth changing your email password to be sure that hasn’t been compromised, though.)