Bad service

I got to an agreement with this company about the car service insurer through telephone everything seems to be ok until I lodge a claim from them for my car that was due for service then the trouble started they tell me sort of stories that I wasn't aware of and I've already paid some premiums and I decided to cancel the policy and demand for a refund witch they refused and now they want me to continue with the payment although I'm not satisfied with their service. Now to my surprise they send me threatening sms's.Are these people ****mers or what?