Cancellation of contract

I have been trying to cancel my data contract since 16/09/2017. I called 808 on Saturday and I was told to call during office hours. Since Monday 18/09/2017 I have been calling but the cancellations line is never answered. I would hold for 20-30 minutes without any help. Yesterday a call centre agent took my number and said the cancellations department will call me back. Today I went to the store in Riverside Industrial where they told me they cant help me I have to call 808. I explained to them that I have been calling with no luck but they quickly dismissed me and they told me that there is nothing they can do. This is strange when we take contracts we go to the store. Now as the customer are put through the agony of calling everyday and pray that MTN takes your call. I am disgruntled about the way they deal with cancellations. I find this a delaying tactic by MTN as the cancellation is 30 days. Than means I will have to keep paying MTN longer than I want to. Now I understand why Nigeria made MTN pay a fine for scrupulous practices.