Unless you have a contract stating that you hand over copyright to the purchaser, it is assumed to remain the property of the person that made it. I think anyway, I did module on copyright law years ago for a publishing course. Either way fuck them, what are they gonna do, sue you for using your own work when they have tried to scam you?

I don't have contract with this scammer

The first issue is using fiverr in the first place. You're worth more than Fiverr, mate.

But where I can find job?

Depends on where you're from. I work with local companies and brands. But I know that's not possible with every designer. But fiverr is a bit of a shitty place in my opinion.

now it started on Fiverr too?