I have tried for several *months* to communicate a debit order change on my business account

I have tried for several *months* to communicate a debit order change on my business account. After multiple emails and phonecalls I have had no response from my private banker. This is not the type of service I signed up for when I became a private banking client. In fact, its absoltely unacceptable for any client of FNB. Very dissapointed and frustrated with FNB