Am I getting ready to get scammed?

I have no time to sell on eBay so I pay a guy to do it for me. I send him pictures and info and he list it then I ship. We've done this for about 10 things with no problems. I told him to list an iPhone 5 and he did so it sold for over $300. Sense then we've sold about 10 things with no issues. Now it's been about a month and half and he says the buyer opened up a case saying he never got the phone and if we can't get tracking hell get a refund.
The guy is demanding I give him $300. He says I never provided him tracking. I swear I did 110% sure I shipped. Its not even a debate. I remember making a special trip to ship it.

If I didn't ship I would still have it
But of all receipts I can't find this one!
One thing that is making me mad he cusses me out and threatens me through text about it. I really think he is about to post my phone number on a public fourm.

what do I do? I really think hes trying to scam me he just threatens me and hasn't sent any proof theyve said anything… What should I do if he post my number on public fourm so people text and call harassing me? Any legal action I can take when he does that

This sounds like a set of circumstances where you're easily scammed. Why would you pay someone to fill out a form on Ebay? That's the easy part - arranging shipping and all is the pain in the ***.

If you can't do something right, don't do it at all. You' sound like you're trying to cut corners here, which leads to problems. It's entirely possible the person you pay to do this is scamming you as well.

When you ship an item worth over $300 to a complete stranger, use tracking with signature required. That's just common sense, isn't it?

If it was delivered, you have the tracking number to prove it.

How is he trying to scam you? Do you know how many millions of things get lost in the mail every single year?
If you provided him the tracking number you would have had an email in your Sent folder. If you don't, then you probably didn't send him the tracking number. It doesn't matter if you shipped it - if you do not have signed proof of delivery to the buyer's address, then you have to give $300 to this guy as his Paypal account will be $300 negative because the buyer filed a dispute

Go to the tracking number and see if it was delivered. Then give that info to Ebay when the buyer opens a case. You don't need a paper receipt, just look at your tracking number under the Sold Item.

Stop getting worked up. Maybe your liquidator didn't ship the item. Ask him for proof of tracking.

Don't pay attention to what he says. Let him open the case and Ebay handle it.

What public forum are you talking about? You can reciprocate if that happens.