Shocking cell C fibre

Shocking service from Cell C fibre. I bought a new property. The previous owners was with vumatel and cell C fibre. I want to use vumatell but are going to go with rocketnet as my fibre service provider. Vumatel says i cant activate my new account woth rocketnet because cell c is still active. I have been phoning cell c every day. Everyday its a different story. The previous owner also phoned them to cancel the line. Vumatel still say they cant do enything because cell c is still active. The previous owner brought is old cell c rooter and said i can use it if its still active. But it doest work. I have been constanty on the phoned with cell c and used over 300 min to try to get this sorted. I am the owner of my property but can get internet.