Subscribed to things I know nothing of

Good morning I received a sms notification at 04:50 that I subscribed to something and I didn’t as I was sleeping throughout the night. I contacted mtn and was told I might have done so. My question to the consultant is how so as I was sleeping. I was with cellc for 3 years and have never experienced such. I regret porting mtn if I’m going to be subscribed to things I know nothing of. Can you please correct this.