Very poor service

I joined bonitas last year(2017) as it took over from commed, the problem started when I got an e-mail from them stating that my Debit order has been returned as no such account, only to find out that they tried deducting from an account from I've closed two years back, to rectify that I had to send my new banking details again and make a direct deposit, the same problem occurred again the following month. Now later last year I was requested to submit my income verification documents before a certain date, I did that, now they wanna put me on the highest income bracket because, apparently I submitted my documents late, I've resent my documents several times and also attached my previous emails to show that I sent them long ago, but I get no response at all, when I call they say the the income verification department does not have a direct line and I should email.