vodacom contract

helo my name is Bongiwe i had aproblem with vodacom so i bought a phone they deliver the phone it was a contract phone huawei y7 2018 i paid the phone clearly never skip any month it was a 24 months when i reach the month of October my last month i thought i was done paying the phone.....but they were keeping on dedacting my money every moth till the following year 2020 when i call them they said i was supposed to cancelled my contract while am telling them that i ddnt know it was my first time taking a contract phone my last paymeny it was this year 2022 May now i cant do anything course they keep on saying Vodacom has blacklisted me this is so painfull please help to clear my name......