Bad service

I spoke to Nicole early September to change my debit order date to the 15th of every month, but came month end my account was debited by M-sure , quired it but till today date I am still waiting for my debit order fees for a debit of end September. Now Nicole tells me to deal with customer care while I dealt with her in the beginning., In April apparently they were migrating their system and debit orders didn't run , I let them know and the told me that it has run through successfully, 2 months later I am told it didn't go through due to the migration system. I asked them whose fault is it and they can't give me answers. They've since said they're investigating till today I am waiting for an answer.