Inability to migrate a contract number to prepaid

I have been trying to retain my number and migrate it to prepaid since the middle of February 2016. Unfortunately, not one employee at Vodacom knows how to do this. I have tried walking into the customer care centre at Vodaworld and was told that they cannot help me. I have called numerous times to the call centre and they have no idea how to do this. I then posted my complaint on fb on 9 March 2016 and Vodacom's social media team have contacted me. They listened to my request but then miraculously upgraded my contract without my permission instead of migrating my number to prepaid. Since then, I have had no joy with them in sorting this out. All posts on fb are blantantly ignored. When I do receive a call, it is normally an apology but never a resolution to the query. My previous comment on hello peter was also ignored. Not sure where to go from here as it is already the 29 March 2016 and all my complaints have fallen on deaf ears.