Contract ended with MTN

my contract with mtn ended on 27th February 2026, i visited the store in early January 2026 to cancel the contract. i was told to come on the 28th a day after the contract ends. they told me to call 135 for cancellation which i did. on the phone the lady tells me that there is 30days noteci befor cancellation. i told her that i was not told that at the store and my contract has ended and i cant afford to pay anyfuther. i am not happy that information was ommitted to me and i have to pay for a month when a contract is expirid. please i need your hepl to end the contract i cant afford to pay and i dont owe them. my email ***