Contract Cancellation

Do not apply for any contract with this network my contract ended on the 24th of March 2024 today they charged me R362 yet i paid up on the 1st of april for march now they are telling me i should have cancelled wich i did call on the 24th to cancel i was even asked if i want my sim to be prepaid or i wont use it.. im so angry imagine not having money and having to pay huge bills of an account that ended long timw ago i regret the day i opened an account with Telkom