Billing incorrect and cannot get this sorted out

Recently did an early upgrade on a mobile contract with Altech. Over the past 2 months my billing has been rather high so I queried it, I have spent the past 14 days fighting with Altech over proper billing. I escalated to upper management at head office and was told I will get feedback but have received nothing. I keep getting the same feedback to say my billing is right but I am convinced it is incorrect.<br> <br> Altech doesn't care and I have reached the point where I just want to cancel my contract. Have had enough!<br> Will be very surprised if anyone contacts me with regard to this!