Double charging clients and not keeping their word

I Am very irritated with Telkom at the moment... We had a landline for the business and the cable kept on getting damaged. So telkom came and said that they will supply us with a Router - Voip (for Free) because they will not be fixing the cable anymore. We then decided we will take an extra phone so that we have 2 numbers. So when the Bill Came in December We were charged for both the Router and the phone - without complaining we paid the Invoice. But to my suprise we received the latest invoice from Telkom and they charged us for the phone again. When you try and phone them you cant choose one of the options it keeps on telling you that you havent chosen an option. When you email them they just dont reply to your emails at all. I need these invoices fixed and credited for the Router that we paid that they said they will give to us.