I'm afraid to say that your contract is valid and if you 'stop' the cheque (by claiming deception, just about the only way you can do it), then you will be committing a rather serious criminal offence yourself. Just like the UK, contracts do not need to be signed manually, you just need an offer, an acceptance, and a consideration (your cheque). You can't claim to have not accepted the contract if you paid! You did have a period when you could cancel (7 days, I think), but you can only cancel by doing it properly; right form of words, sent LRAR to the other party in the contract. Also, you say that the insurer is in London? That would have an impact, too, although if the contract was established in France, French law would apply. Remember that the garage has (I believe) 1 year and 1 day to cash your cheque, so watch out for the anniversary. If they don't cash your cheque, it doesn't remove your obligation to pay. Sorry about the formatting, but this forum doesn't seem to like Chrome.