in arrears after having paid for the movies rented

I deposited some money into my Box Office account via Eft to rent two movies, only for multichoice to claim the money for two movies I rented in the past but never paid for. I always sms the rental codes to them so I have the message thread on my phone for every movie I've rented and paid for. At all times of renting I always ensured that i had sufficient funds for the rental and if i didn't have funds available then I would get an sms saying I have insufficient funds. How is it that I've rented movies that wasn't paid for??