Bad service , responses

Good day, I would like to put a complaint against Supersonic. I purchased LTE service from them needless to say they sent me the rooter on the 24th July with NO sim card. I phoned them numerous times NO Answer, I even went to there offices in Constantia office park hoping to find someone to help me , no one was around because I think they all working remotely which is understandable . Seeing we all in this situation. I reported it numerous times and took them 4 days to get back to me and only because I laid complaint on their website. I finally received the sim card on the 30th June . Today I still dont have connection for a service I paid and still and still no responses from them. How does one deal with such bad service in such trying times. They took money from and countless of other people and not giving a promised service. I want my money back Supersonic is the worse company and they lie to get clients money.