Promised me 25% discount and bills me full amount!

i was promised a 25% discount if i stayed with Telkom and not change to a different Internet provider. I accepted the offer based on the 25% discount. I have not received any form of discount what so ever and i am currently being charge the full amount which was not even agreed. I have been phoning numerous times for assistance on this particular matter!!!!! Every single time i contact the billing department they provide me with a reference number and inform me that someone will be contacting me withing a few days. I have yet to receive any form of feedback let alone a phone call from this particular department. I need this to be rectified NOW as i do not even know what amount needs to be paid! according to your records i owe you nearly X amount which is BS!!!! i will not be paying that amount as that was not agreed between me and yourself! i do not know what to do anymore. No one is contacting me back with a solution ! this is EXTREMELY ********* and unprofessional. I do not know how you conduct business but it is certainly not acceptable. I will be taking this matter further, i have informed my attorney and have saved all the emails promising me the 25% discount. SORT THIS OUT!!