Vodacom poor service

I have been having an issue with my line since I migrated from contract to prepaid, I don’t receive calls from all my contacts, all the numbers that used to call me when my number was still on contract. The issue has been happening for +5 months. I have tried logging incidents with customer care, went to Vodacom Menlyn to have the issue resolved but they are unable to resolve it. It’s frustrating as I’m unable to receive calls from my family and friends.