Harassment for account not paid, although it was paid.

I have been harassed by the Mr Pirce/Miladys group over the past month. According to them, I have not paid my Miladys account for January, although I sent proof of the amount being deducted from my banking account. This is absolutely ridiculous. I will NOT pay a single penalty fee for YOUR incompetence. Closing my account and Miladys will never get support from me again. They have gone as far as to call my personal contacts. Unacceptable!