Unhelpful customer service

I am an account holder of 2 contracts at MTN. The one phone was a gift to someone. MTN allegedly has a 24 hour customer service line. When calling because the phone was ******, and asking them to block it at 8pm on a Sunday, they said the department is closed. I think it is bizarre that there is 24 hour assistance with ****** phones at MTN. I call the next moring to block the phone, this was also an issue with the agent and the Manger I spoke. The agents were unhelpful. As the phone was puschased with them, but they could not block it. I strong regrette signing a contract with MTN.