Discovery refuses to assist

I contacted Discovery Insure to Double debit my bank account for my premium for this month, April 2019 on the 5th for May 5th 2019,the consultant indicated that that is not possible because their system will try to debit on the 20th of April. I explained that due to a double debit by their sister company, Discovery Health, as I started a new job, the funds won't be available. As my salary is only due on the 28th of each month. The consultant refused to assist and said that a manager will say the same thing to me. Which means my car insurance will be canceled on the 20th if there are no funds. Other insurance companies allow double debit orders, why can't Discovery Insure?