Number deactivated before the end of the month

The contract number .<br> <br> I requested the 3G contract *** to be cancelled last month on 31 May 2015. This was a 30 day notice as required by CellC.<br> <br> Last night the sim stopped working. Today it was confirmed by customer service that the number has been terminated. The problem is that I reserved the balance to be used the last night. I have lost 7GB on the number. I am not prepared to pay for the full amount now that a significant portion of the data has been cancelled EARLY without warning me.<br> <br> Please confirm you will REDUCE the last instalment due to the EARLY termination.