MTN DATA CONTRACT

MTN data contract issue not resolved.. I signed for 80 gb data monthly which is 40gb day and 40 gb night express and they only give me 50 gb monthly which is 10gb day and 40 gb night express instead. I have been complaining about the issue to them not keeping their end of bargain as per contract says... The contract started on August and it was fine for only 2 months so after it's just chaos after chaos yet they deduct every month......