You have got to be in a fairly bad place to use a company like Wonga or similar.
If all other avenues of credit have been exhausted and you are using them then chances are you are not the most credit worthy person, but then should that be exploited by these "pay day" companies?
You can argue if they make their charges obvious and you accept that you are paying a massive chunk of interest are they actually doing anything wrong?
No-one forces these people to borrow the money, so before we start bleating about interest rates and fake letters being sent chasing the debt, lets look at the real issue - People want nice gadgets, phones, TV's and dont really care how they get it as long as they do and then keep up with the "Jones's".
Borrowing money on any scale costs - if you can't afford the repayment, dont borrow the money. If you are borrowing check the interest rate - a simple calculation of monthly payment x number of months will give you the total paid, i think FCA rules now means you have to be told this anyway but if im wrong then the above calculation is fairly straightforward isnt it?
We can kick out at Wonga type companies all day, but we have to address the issue of people borrowing outside of their means - Wonga IMHO are just a means for people to get things they can't afford or shouldn't have.