Vodacom deducted money with any explanation

Vodacom debited R1521-22 on 7/3/2019. Since then I tried to call them. After holding on for +- 50 minutes the call was eventually answered. I was informed that I did not pay may account for February 2019. On 28/2/2019 an amount of R430-09 was debited from my account. Vodacom can not tell me why an amount of R1521-22 was debited. The call centre agent clearly does not have the required knowledge or training to deal with call centre issues. Promises was also made to me to send my a detail statement and nothing happened.