Bad telephone lin

I have about had it with DSTV and it's bad service. I spoke to two agents today who could hear me just fine and assisted me with my queries after some difficulty as they are all idiots. i was transferred to the dstv mobile call centre for another query and apparently there is only one person the whole department who has a very bad line but refuses to admit that it is his line that is and also refuses to call me back from another line or to transfer me to someone or to get me a manager to talk to. I'm calling from my office line as it is quite a pain to call from my mobile as your voice system just wastes my time and money. he expects me to shout out my personal details to him over his bad line for my entire office to hear. I don't see how his bad line is my problem and when i tell him it's his line he refuses to admit almost like he calls himself and know that it's not his line and how can he be the only person in the entire department who works there. That just makes no sense. My customer number is ***0. Very disappointed client once again!