Is there any way to fight this with PayPal?

I had sold some things to someone and had them pay with PayPal. The day after I mailed their items (I told them a few days prior that I was shipping it on that day) they filed a claim against me saying they did not receive their items. Of course they hadn't received them yet, they were just mailed the day before and they were aware of that.

So we went back and forth in the PayPal chat and then PayPal intervened and asked for tracking. I stated the customer had the option of free shipping that did not have tracking, or they could pay extra to have tracking. They chose not to have tracking (obviously, I have learned my lesson and will now require tracking on all orders).

So since there was no tracking, they sided with the buyer. Now my account in negative $90 and I can't afford to pay it. My account is basically locked until I pay it.

Clearly, it was the buyer's plan all along to scam me and whoever handled the claim did not see that. Is there any way I can appeal this or something?