Not Happy with their service

I have changed my banking details by October which they have told me its too late I must pay by EFT I have asked the to please do the forst debit since i cant do EFT which they did it on the 06 Nov amount of R460.79 again on the 09Nov they deducted which I have disputed so now they are saying I am 1month short by the 25Nov they have deducted R460.79x2 been calling them and emailing them since Monday the 23 after I have received an email saying I will be deducted double with no luck I even ask for the Manager whom did not respond to my emails and answering my calls her name is Estell no one is bothering on answering my calls or getting back to me or calling me at all