Bad service

For 2 months I'm trying to change my debitorder on vehicle finance, first they said I must phone them because the do not work on e-mail request, then they said no I must send an e-mail. At the end of January I phone again because it wasn't done. Then I need to pay the money in and send an e-mail again. I e-mail again twice and phoned them as well and still the change wasn't done and the installment not paid at the end of February.