RUDE SERVICE AGENTS

I spoke to Minkie who is working from home and is very rude. I was calling from a landline in regard to my MTN number and she refused to help me telling me that I must call from my mobile phone. She did not even want to listen to why I was calling from a landline. I have a network problem where I am and the best option is to call from a landline. I called from my mobile and the next service agent said they can't hear me and hung up. in this manner, you will lose clients. how am I supposed to get help then?