Contract cancelled without my knowledge and permission and R800 airtime gone!

My contract was cancelled without my knowledge and permission. I had about R800 airtime and after the cancellation the airtime was gone. I have contacted the call centre since June 2017 and nobody can explain why or where....numerous failed attempts. I have 5 current vodacom contracts with Vodacom. I am sure it must count for something? I want answers please. I did not sign ANY forms to cancel or over the phone. On my first call the call centre agent assured me that i will not lose my airtime. I called again in August to query again. I spoke to Mzwake Maluleke on 13 August 2017 @ 14:11 and 14 August whereby he assured me it will get sorted out. I am still waiting. Please assist me.