Debited 2x monthly premium

My son sent the email below on 3 and 9 March. No reply.

Watch out, Liberty debited twice the amount of the monthly premium in one month. ********** Good day

Why did you take double of my premium from my bank account? My premium is R1331, not R2662. Please refund me R1331 and tell Standard Bank to not charge me bank charges because you caused my bank account to go below R10000(minimum balance for Rebate option).

RA policy

Thank you Mr Lee