Overbilling

Vodacom has over billed me and when I called they advised that there is an error on the invoice but when I called the billing department to rectify the issue my call is directed to a chatbot that is not even helping with the query. This is really ridiculous and frustrating because how can you make a mistake on the invoice and when this must be rectified I am not getting any help. I guess I have to refer the matter to the ombud.