Diamond parking again. Many years ago, I also had my FINAL notice without physically having a ticket. And the funny part was that the ticket was from a place that my car never visited. So obviously that ticket was wrong, but they don't listen.
Soon, their collector agent started bugging me (it is actually they own department, just diff name). Like you, I don't want to bend backward to pay for this bogus ticket. I sent letters and my wife helped talking to their agents (she is better in bargaining) a number of times. First they offer to reduce the ticket price which is BS. Anyway, after many calls, they took it out. All you need is lucky to have a good agent on the phone with you that day.
I hated Diamond so much since then. Yes, be strong and firm, and prepare to spend time with them. Like other said, even their collect agent can't do much harm to you, so don't need to worry on that part.
I read on some site before when i was looking up Diamond and Impark, both crooks to be honest. Their staff gets commission per ticket SO... Hmm.
Back to the info stuff.
Some guy who worked at a decent position inside Impark said that... probably true considering there are no other ways they can find your name, address, and phone number with just your license plate number? I would probably word it as "ICBC sold info to these companies" rather than "companies bought the info
I parked in a 3 hr limit D. parking lot for 2 hr & got a ticket saying that i parked over 3 hr limit.
I called their customer service, tell them they issued the ticket by mistakes; the agent wanted me to prove that i didn't parked over the limit or they won't cancel the ticket. WTF?
They made a mistakes & want me to prove it ? i asked them how could they prove that I parked over 3 hr, they can't prove it either. (it was a hand written ticket, not generated by the hand-held machine which they input your licence plate# & then check again 3 hr later.)
the agent replied "they won't issue ticket unless i parked over the limit, bl ah blah blah..."
Also i called ICBC, the agent replied me that ICBC DOES provide customers info to parking company upon their request!!!