Vodacom contract cancellation

My mother passed away and I have been trying to have her Vodacom contract cancelled. This how turned out to be somewhat of a nightmare.

I have sent the documents to them twice (I have two reference numbers) and followed up with legal call centre multiple times.

My calls have been dropped, legal sends me to subscriber collection who sends me to legal who tells me to send the documents again.

The back office does not even attached the documents to the account, legal says they cannot attached them and will not even accept the reference numbers from me.

In store sends me to the call centre who does not assist.

I do not what more to do. I am pretty sure the next contact I have from Vodacom will be a legal one about money owed when I have tried to follow the proper route.