Bad service

I called the dstv contact centre and stated my problem which is they deactivated my service without any notification when i spoke to the agent he said an sms was sent to me which i never received and he was adamant that i received the sms im lying. I called again later spoke with another consaltant the same happened so im lying against their system instead of saying they will conduct an investigation with their IT department and call me back. I asked them who is liable for the R50 activation fee they said i am i their own words because im lying against their system