Non Existent Customer service with managers and Executors ignoring emails and complaints

MTN has the most appalling customer service. We use them for data at our office - the tower providing this data has not been functional since Oct 2022. To date we have been promised a repeater - still waiting. Our office signal is non existent and we are unable to make calls on MTN. Our contracts have expired or been automatically renewed without communication. I have emailed every person possible including their director of communications but nobody responds. I have tweeted as well but still there is no response. What must one do to get a response from this organisation?