Unable to cancel my contract

In 2020 I upgraded and got 2 promotion phones and a sim which was due for an upgrade February 2022 I ended up upgrading on the 29th March 2022 and only took data. I told the consultant that He must cancel the second number since I wont be using it as a contract. Today I discovered that I won't be able to cancel because the contract has already been topped with airtime and I have to pay for the contract until July 2022 or pay for the cancelation fee. Why am I paying for the cancelation whereas I spoke to the consultant before the 1st of April to cancel?