I got one of those emails from Royal Mail on Monday. It said I missed a delivery, and I actually had missed one that day, and the calling card didn't have a reference number left.
So I clicked on the email and stupidly entered the details it asked for ..
name on card
Address
Email
Phone number
I just canceled my card just Incase, but do I have to be worried about them having these details? I am so sleep deprived and stressed!