Consultant just sells

I am super tired of MTN not sorting out there issues!! My finacé has received a data contract form them and did not tell her she can only use it in the router. After the first week she called to cancel the thing as the consultant was in the wrong as she admitted but to date it was still not cancelled! It is now almost 6 months and they keep on phoning her to oay the account. If this is not sorted by the end of the week I will take legal action agains MTN south africa!