Wrong debit amount

I opted for business insurance while doing business, I phoned them to inform them I'm about to stop doing business and would like to cancel the insurance, they forcingly gave me a quote of personal use insurance which I refused to take. They went on debiting business insurance amount which was on mendate, after I moved my money so that they don't have an access they've reduced my installments to comprehensive without my consent, which was debited for the past 3 month, I officially stopped doing business mid last month but personal insurance has been going off for the past 3 months , had I been involved in an accident while doing business it means I would be not be covered so basically I was not covered my question is why did they go on and make debit orders that we didn't agree apon? I want my full refund for the past 3 months.