Discovery Insurance policy update

Annual insurance policy renewal was emailed to me with 25,6% increase, despite no claims (except for forced replacement of a windscreen as per Discovery rules related to cracks). This renewal was rejected and I requested a better quote of the order of 7%. I received a second quote with 16,7% increase, which I again rejected. I received no further response and Discovery proceeded to debit my account for the second rejected amount. I emailed again and strongly objected to this. An agent called and I had difficulty in reaching any reasonable reduction, but eventually this was achieved. The assumption that I should just accept 26 or even 16% increase, and to proceed with debiting my account without approval is unacceptable business practice, especially when Discovery is making large profits.