Drafting a particulars of claim - to sue a used car dealer

HI
drafting a particulars of claim.
need to help to draft and compile particulars of claim.

I can provide you with a draft of all the details required in, I need the context of description clearly crystal clear written to the defendant .judge.

claim outline
a used car dealer mis sold me an faulty car, within the 30 days he tried to fix the issue, which failed, now I've paid money to fix the issue, now im claiming a partial refund from the dealer to cover the cost of repair. but after fixing the issue with car the dealer now wants offer me a full refund. but to late now.

THANKS