No answers or refunds on incorrect invoices

I have been paying 150/month for absolutely nothing for 24 months (i pad). Vodacom does not refund errors on accounts. They do not reply to Queries or complaints. Now after many years wit this provider i have been threatened to lose specials. I am only happy that i am free to consider other options. This they now do since I am a pensioner who cannot afford their false invoices any longer.