Cell C bad service in cancelation of contract

Once again I am disappointed at Cell C. Mr Mo***eng contacted us and said that our contract will be cancelled from 25 July 2019. Our contract was R906 pm. We will only pay pro rata until the 25th of July 2019 and signal will also stop on same date. Our signal was cancelled on the 20th of July already. On 01 August 2019 they deducted R960!! More than we paid monthly. *****ing from clients? Please give a valid reason for this and refund please