BAD SERVICE & CALL CENTRE TAKES TOO LONG TO ANSWER

I called the Old mutual national call centre I cant remember the exact date but it was the middle of March 2018 and spoke to a call centre consultant by the name of Yanga and told her I need my banking details to be changed because I had changed my bank from Capitec to Nedbank the Lady helped me and assured me that they were changed. Today the debit order went through but they only deducted R226.00 INSTEAD OF R394 which is the amount I've paid since last year. I called the call centre and they only answered after 30 minutes and I spoke to a lady by the name of Jasmine who told me that Yanga who changed my banking details didn't do it correctly that's why they only deducted R226 and the rest of the amount was deducted from the capitec account and that the account doesn't have funds in it and now the debit order will come back as unpaid and this will have a bad effect on my credit report. I want Olm to confirm that this will not have a bad effect on my credit report because I'm planning on buying a house and right now I Feel like cancelling my policy with OLM because the staff don't know how to do their jobs properly.