Wrongfully debiting my bank account

I have been with Kingprice Insurance for my car insurance for many years with no claims. I sold my vehicle two weeks ago and thus had to cancel my policy. I then purchased a new vehicle and took ownership on 21 February. I contacted Kingprice insurance to provide me with a quotation prior to me collecting the new car. The quotation provided was too high and thus adviced the consultant that I will try to get another quotation from anothe insurance company. The consultatant advised should I need a better quote then I must go elsewhere. I then had another consultant from Kingprice who called me to see if he could help to retain me as a client. He also gave me a quote I was not happy with. I then contact another insurance company who gave me a much better quotation. I joined the new insurance company. On 21 February I had a guy by the name of Justin from Kingprice who called me advising me he can better the insurance premium. Advising me there is no other insurance company who can match up to them. I told him in all the years I never had a claim so not sure about their service levels but there are no kickbacks on no claim bonus. He forced me to stay on and becoming absolutely annoying asking me to tell him which company I am joining, I advised him I am not at liberty to provide him that information. Today I decided to log into internet banking and to my horror saw that Kingprice debited me for an amount of R554. Dishonest ********* people. After all my debit orders for all the years which was always paid on time and all the business I gave them this is what I get back. Dishonesty. To me this is theft you cannot take monies from someone's account when I no longer have an account held with them. When they came back to me today there was no definite answer as to why they did this. But I'm sure with hellopeter they will claim it was a sheer mistake. How pathetic these people are. If you wanted to retain me as a customer why didn't you provide me with a better quote right at the beginning, why did your consultant advise me to go look for a better quote, why did you just debit monies from me after me disagreeing to your quotation. I am a stage 4 cancer patient and very ill. I do not have time to fight battles for my monies that was debited from my bank account for no reason. I am not working currently since my diagnosis so every cent counts for me. U guys needs to get your act together. Don't go around doing this to people.