Re: Far too common
Next time give them a PAYG phone number and a forwarded free email address that you have never given anyone else.
Cost: Pence.
Impact: Nice letter winging it's way to them and the Data Protection ombudsman saying you've totally abused the data I've given you without permission and/or failed to secure it and not notified me of a breach... which is it?
P.S. Have done exactly this. Have screwed company to wall who used a stolen customer database. I know they did because (in my best Del Boy impression "That's not the hand I dealt you...") this case... That's EXACTLY the email address that I only dealt SOMEONE ELSE and not you...
Biting the hand that feeds IT
