Security questions

I made a mistake last year November when I used the banking app to pay for the monthly premium by not inserting my contract account no as a reference. I usually pay through the app beforehand to avoid missing the payment every month. The same amount that I paid was taken from my account although I already paid in the beginning of the month

I tried to call several times for a refund but the consultants kept on telling me that I failed security questions even when I gave them every correct detail that they asked for and also that I should log in to my profile to check the information. Also went to the store for help but received poor service because the consultant was rude. It's been a year now and this is the last month of my contract.