how we can trust a freelance writer ? and wht we can do if a frelancer failed to turn in the paper ontime?
Realistically, the first time you use any writing service you're taking a risk, pretty much the same as with a new car mechanic. Whether you try a company or a private freelancer, you should place a small order first instead of waiting until you need a big important paper. There are probably fewer private freelancers who are dishonest because it would be much harder for us to earn a living based on first-time/last-time customers than a commercial scam company that processes hundreds or thousands of orders every month. We depend on repeat customers and word-of-mouth referrals and couldn't stay in business on one-time customers.
If you paid by credit card, you could probably dispute a charge for essays never received at all or for plagiarized essays, or for essays sent a long time after the deadline, but probably not for missed deadlines of a day or two unless you have some written agreement (or an email exchange) that specifies that "time is of the essence" or that spells out a specific penalty for missing the deadline at all.
If you paid by cash or wire transfer, chances are you're out of luck even if you never got a paper unless you happen to live in the same state, it's worth your while to pursue it in small claims court, and you know the writer's actual name and address. If that particular state happens to have any statutes prohibitting academic ghostwriting, you're screwed unless the small claims arbitrator or judge isn't aware of it.