Being charged after cancelled line

In end of February I wanted to cancel my Telkom line from 1st april as I was moving house. I spent 10 days trying to get through to someone and over R400 rand in airtime as I could not get hold of them when I was at home to use the Telkom landline. I tried contacting Telkom at least every 2 hours for 10 days every single day. Only after 10 days did I eventually get through to someone beginning March. When I did get to speak to someone to cancel my account they insisted because I only phoned 10th march that I will be charged until 10 April BUT it was not my fault I could not cancel the line because I tried from the whole of the last week of feb - they did not answer the phone for 10 days so it is not my fault I could not get hold of them before the beginning march. they then cancelled my account on 10 march. Now I have received a bill for being charged for 2 months (all of April and all of may) even though I cancelled my line. I have had enough of Telkom!! I even asked the person on the phone from Telkom if they were sure that my line would be cancelled in april and they said yes. ABSOLUTELY FURIOUS!! I have put through 2 emailed complaints on their website and had no response.