Charge for Box Office rental but no movie received

On 1 May we attempted to rent a movie on Boxoffice. The movie never came through even after trying repeatedly. Each time we retried we got an sms saying the previous rental was unsuccessful, we would not be charged and that the movie has been resent. However it never ever came through successfully. I assumed given the messages that unsuccessful rentals are not charged.

Then on 8 May, we tried again (for the same movie) and again not successful but my balance was now showing that I had been charged for both the 1 May and the 8 May rental. I now called DSTV and advised but they said that because I did not call in 48 hours the 1 May charge would not be reversed. How am I supposed to know that I needed to call them within 48 hours?

The rental for 8 May was loaded manually but even though it is not a huge amount of money I feel it is very misleading that I got charged for 1 May as I did not receive what I rented