I am really sorry to hear so many people have been caught by this scam. Write to people like Polly Toynbee at the Guardian, who has already railed against Wonga and all they stand for, and to your local MP. If enough of us did that this would get more attention.
I know you think it is silly and worthless, well most of you anyway, but your MP is already paid for, and newspapers are often good at making people who can do something take notice. There is a thing called the Protection from Harassment Act 1997 which allows for you to take someone to court if they persist with a course of action that you can show is not valid. For example, if you tell Wonga not to do this and they persist. Action can be taken by you simply in the Small Claims Track of a County Court. A lot of people pursued by parking companies have successfully used this to get wrongful claims off their backs.
Thanks for the warning, it is appreciated. Nonetheless, if we all think this is bad and want something changed, we have to go to a bit of effort. Write to your MP tomorrow - their details are
here.
It would take you no longer than a post on here to email your MP and tell them how this is going on, it is wrong, and what are they going to do about it. What's to lose - five minutes of your life at most. If your MP ignores you, then drop an email to your local paper and say so, they'll soon get back to you!