Unable to rectify mistake made on profile

I've used Wonga many times before. I try to keep my information as updated as possible. I've updated my employment details online on my account and made a mistake with my \gross income' after which a service consultant told me that there is NO WAY this can be corrected. I should wait the 30 day period after which I will be able to change it online. This is unacceptable and I cannot understand that they have no way of assisting a customer with something like this. "