Really love that app! After short set-up I have entered difficult invoices and... after couple of polite messages from the app the money was on my account! :) I have also recommended the app to my friends and as far as I know they have also succeeded in collecting their money! I really recommend that app! And so far the app is for FREE for new users. The offer is time limited so do not waste your time, get the app and collect your money from tyour difficult invoices and bills.