Impossible to cancel

My contract that I have with them ends on the 28 February 2021. You cannot cancel by emailing them, you cannot cancel by calling! I've never heard of this ever in my life where you as the customer has to call in exactly on the 28th of the month to request the cancellation or you cannot do it before or after. Such *******! No managers work at Cell C either. The agent then advised that if I want to cancel the contract now I should pay first! I will never do business with cell c ever again and I would never refer the provider to any friends or family.