Telkom is a ****

I took a contract of R199 with telkom. They ended up deducting R900.and this month they took R600. They said i missed the payment but i have never ever missed payment, i have proof. Now they have putted my account in arrears. They jave just sent me a msg saying they will deduct R200 from September Last year to date. They have ****** a lot of money from me. I am cancelling my contract with them because they are not helping.