Unfortunately the Internet is still the wild West. It is also a worldwide platform which does offer some form of anonymity. You have to remember that not everyone is as nice as you and some people are out to rip you off.
There are a couple of ways you can avoid getting scammed or at least minimise the risk.
Place a small test order.
Before dealing with any supplier on ongoing basis, you really should place a small test order first. You should make sure this test order to sent directly to you or someone you trust. The selected test the supplier before you build ongoing relationship.