no debit taken till I queried and then 3 at one go

I had a system installed in December. At the end of January there was no deduction. I then queried why no deduction. Eventually after two or three emails I get a response to say it was too late for January billing and they will deduct December Pro-rata, January and February at end of February. I asked them to explain how can they do this. There was more than enough time for January to go off. Also had I not queried this there would still be no deduction. I called them to speak to a manager and was promised a call back as the manager was busy. More than a week has passed and I have had no call. In two of the email responses it was stated that the matter has been addressed with the billings/accounts area and they will contact me with feedback. This has still not happened either. Surely for such a big company this is not the way to treat customers. I would like to know what would have happened had I not queried the deduction. I also want to know why I was not contacted to be explained what had happened and to clarify the matter with me. I did not give permission for you to deduct this amount. Only the amount per month. Own up if there was error and discuss with your client.