Refund of my last debit and cancelation of the contract

Telkom deducted R749,00 2nd July. Today it's the 31st of July 2021. And I debited again R 932. 00 Whats funny is my cellphone contract ended end of June. R749+932= R1681 All in one month. Had been calling the center for the entire month of July asking them to move my account to prepaid since it's ended. But no one got to assist me. This morning the last agent told me to dial 180 and choose option in both 180 and 188 there's no such option. Please assist me because I tried to get assistance from telkom but they are not assisting me