MTN

I am seriously annoyed that MTN are allowed to phone people early hours of the morning, with recorded sales voice message. I received a phone call last night at 1.17 pm. Woke me up and as both our children live overseas, always worried it might be some sort of emergency. Answered the phone half asleep, to get a sales voice note from mtn.!!! This is an invasion of my privacy, let alone my sleep. Surely this is not allowed