Discovery Car Insure - Poor Service with Refunds

I had Car Insurance with Discovery, and cancelled on 30 August 2018, still debit order for September on 2nd of September 2018.

I have asked Discovery for refunds and they informed me that refund was initiated on 3rd September 2018, I have been waiting for more than 6 days, since now no response even after sending multiple emails, instead they are asking me to raise request from bank which is unfair and it involves additional cost. I have still asked Discovery to process the refunds. Discovery should know how to treat their Customer fairly.

Such a poor customer service from Discovery.