Billing Dispute

I am a telkom customer and have an ADSL package : Telkom Simple. My internet was down for the entire month of April. I tried calling telkom's customer care but there call center did not answer for hours or when they finally did, the line would conveniently be cut on more than one occasion. My line was reconnected on Tuesday 12/5/2015 at 10:00.<br> <br> On 10 May, the very same day of reconnection, I received a bill via email for the use of ADSL for April , May and June. I had no internet connection from the 31st March 2015 until 10am 10th May 2015. Why am I being billed for internet which I did not use? Also, I am not sure whether it is usual practise for Telkom to bill in advance as per invoice 9 May - 8 June 2015.<br> <br> I do not want to pay for adsl for 31st march to 8 may. I would like for this matter to be rectified before the date of expected payment for my account which is 1st June 2015.