Bad pathetic service

We cancelled our contract, giving 30 days notice on 30 April 2015. Reference number 010U~Ul2E, as give by automated response. Until today still no response further from Vodacom. We stopped using the cellphone 3 April 2015 but got billed end of April for R 2746.25!!!!! Really? Who used our phone? The simcard is still in my drawer. We complained about it in the same email to customer services , still no response. I took out a new contract at Cell C, so Vodacom lost us as customers after 12 years!. Somebody in Vodacom also tried to take out a contract on my son's name! It was luckily cancelled , but took almost two months to be done. Who is following up in Vodacom how this happened or is it all shush shush! Was it ever reported to the ***** department? I will NEVER EVER have anything to do with Vodacom ever again! We also will not pay the account until we know what the bill is for!!!