Car warranty advice please

Hello. I brought a 3 year old car from a car sales company on 30th October. I was told I had a 3 month basic warranty but I could buy an optional 12 month gold cover warranty which covers everything for £250. I asked 1 question which was “what is the excess charge for any claim”?
I was told there wasn’t any, only the £250 for the product, so I proceeded to buy this extra cover for piece of mind. The trader rang the warranty company and after myself speaking to them to confirm my details I handed the phone back and he paid for my warranty using his own credit card. We then sorted out my payment for the car and the extra warranty cost by bank transfer. I was totally happy with everything at this point. The next day I received the warranty policy docs via email and whilst browsing through them I noticed that because of the mileage of my new car i would have to pay 30% of any repair costs, going up yo 40% when I drive another 6000 miles. In the cancellation section it also stated I had a 14 day cooling off period. After thinking about it for a few days and ringing around other warranty providers I decided to cancel. I rang the warranty company and they told me that as the trader paid for my policy on his card he would need to deal with the cancellation. I rang the trader who blagged me for a few days by saying his broker was away and he would get back to me, he never did call me back so I ended up power calling him. He finally answered on day 13 of the 14 day cooling period. I explained I wanted to cancel and be refunded again as I felt I was miss sold the product because of the unknown excess charges. He said he would never have said that and tried to sell me excess exemption fo another £90. I refused and again said I want a refund. He point blank told me he won’t do that and he’s going to hang up as I was shouting at him(as annoyed as I was, I wasn’t shouting). He then hung up anyway. I did document my intention to cancel with the warranty company and did send a citizen advice template letter asking for my refund via email. I also asked to speak with the traders account manager at the warranty company but was told there’s nothing they can do. However I don’t know what else I can do as no one seems interested, can anyone advise on my rights or next move please. Thanks