Account Billing

Please advise if the amount of R561 appearing on the statement is the amount that is going to be debited on my account on the 20th of Jan and if so why? Because the only 1GB I purchased on my acc was in the beginning of Dec which I was billed for on the 21/12/2015 now this 1GB that is showing on this statement I have not received so why is it being billed.<br> <br> The above is an email i sent on the 11/01/2016 should I not receive a reply by tomorrow I'm going to your payment on my account.