Bad service

Hi I signed a data contract with telkom in cradlestone mall and after the first month with the contract it was disconnect n I went to the branch to qurie n I was told that my account dont have money so the debit order bounce..so I went to print my bank statement so that we can verify..only to find out that the consultant that was assisting me with signing the contract wrote the wrong account numbers ..now they say I need to pay R1500 for all the months but they are the one that made the mistake and only used their data for one month and contract was for me to pay R139 ...till now no one from their head office called to rectify the error