Earlier quoted context omitted.
In the UK, even if you've managed to buy emails it's of no use, you aren't allowed to contact people unless you've had a business relationship for a related product in the last 12 months.
This is new to me. How does this exactly work? Can you report the email senders to someone, if you get spam or something?
http://www.legislation.gov.uk/uksi/2003/2426/regulation/22/m...
http://www.legislation.gov.uk/uksi/2003/2426/regulation/30/m...
Judges range in how they feel about these complaints, generally you won't be able to claim just for the time they've wasted, you'll have to justify why you have suffered damages. Extreme cases are different, if they're truly wasting huge amounts of your time, but the occasional email is unlikely to be enough for wasted time.
Alternatively, you can get the ICO to tell them off even if you haven't suffered any damages, but that's not always easy…