@Edent my two takeaways here is:
My bank should call from a proper number that gets a proper name even if I haven't saved their number. I don't know what you call this, but like when Amazon calls me for packages, the name "Amazon India" appears below the number. All banks and companies must use such thing.
Then, whenever suspicious thing happens and if the user didn't pick the call, they should immediately send email, text, WhatsApp or whatever to alert them.
@Edent Like they spam you with promotional offers on all the emails, WhatsApp, phone, SMS etc. periodically. So why can't they do the same during emergency?
Sorry for the rant.