How can you bill me after my number was ported?

I ported my number from Autopage to Vodacom at the end of my contract. For the port to be successful, my contract had to have expired, it had to be in good standing, basically it had to be approved by Autopage. Forms were sent from Vodacom to Autopage on the 11th May, port was completed 13th May. <br> <br> I then received a Jun bill from Autopage. Let's not even get into how long it took for them to respond to my ticket requesting that the bill be reversed. On the 18th June I receive this closed ticket reason: \Kindly be advised port activation was received the 04/06/2015 ". On the 30th June"