Unauthorized subscription to Bigcash

On 25 Dec 2022 I got a text stating that I have subscribed to Bigcash on R3.00/day. On 24 Jan 2023 I got a text reminding me that I have subscribed to Bigcash. I don't even know what is Bigcash neither how one subscribes to it. When I try calling 180 to speak to a consultant, there is not even an option to speak to a consultant