Does Telkom automatically stop my contract when I port out?

Hi there. I want to port back to Vodacom. I think my contract only ends a bit later in the year, August or round about there. If I port my number over to Vodacom without converting it to prepaid, does Telkom automatically charge the cancelation fee to my account and cancel the number on their side? I know I can go into the store and convert to prepaid first, but my past experience with their agents in store and 90% of the time @ their call center have been terrible so want to try and avoid it if I can.