I recently accepted an hourly offer from a client but I haven't worked on the contract yet or recorded any hours
and I'm suspicious about the client might be something wrong or spam or something like that because his account is new and no records for any previous job hires.
and I'm thinking about ending the contract does this could impact my profile JSS or the client could give negative feedback without starting on the contract?
If you decide to end the contract and there are no earnings on this contract, the client won't be able to leave public feedback, but they can still provide private feedback. If the client provides positive private feedback on a contract with no earnings, that contract will be excluded from JSS. If the client specifies in their feedback that the contract had a negative outcome, that will be counted in the score. If the client doesn't provide private feedback on a contract with no earnings, that contract will be excluded from the JSS calculation.
If there's anything in particular that makes you feel something is wrong with this job, I suggest you report it so the team can look into it. In this article, you can find more information on how you can report suspicious activity.