Burned by sellers

I have been burned by two sellers.
Seller 1 : purchased using the ship service through OfferUp. The sellers never shipped the product. I lost my money.
Sellers 2: a local sellers of services ( I paid for a railings to be made) the sellers came to my house I got an estimate and paid the deposit. Made the schedule date to install and he never showed up! He ignored my calls , texts!
I have been burned twice. I continue OfferUp and no results no money back!
Lost trust in OfferUp and sellers!
Level 9
OfferUp can only ban someone after the fact.

And provide info to police if you have filed a police report.

The first one you can file a buyers claim.

The second one, services like that are against the rules.

Exchanging numbers is ill advised.

At least it's a learning experience.

Report both users either way.

You can also report the second one to some gov agencies if he has a business.