Contractual dispute

My name is mzinsisi peceverance Manitshana I'd number *** I have a problem with telkom.i had a two phone contracts with them until July 2021.they told me I owe them 1284 rands I went and pay at pick n pay.when I phone them to terminate my contracts they told me I still owe them that amount and they said in one the number they me about 800 and something and they said I must email the proof of payment and I did that,last week they told me I owe about 400 and something.so please help with this problem