Computershare
Struggling to have banking details changed for div

I have now been struggling for a month to get my banking details changed, so that my share dividends can be paid to my correct bank. Every time I phone, I get a different story why it can't be changed or has not been changed. No I am so fed up with this, that I want to sell my shares and move to another place, but the phone just rings all the time with no answer.