"I had a great seller rating with nothing but good feedback and reviews" 

But  still a low feedback score.

Did the buyer who left you neutral open a claim  for  "item not as described"  under eBay's Money Back Guarantee ?

Yes, it's happened to others.

Have a look at the information in this link.    There's an option to  "Request  A  Limit Increase"

https://www.ebay.com.au/help/selling/listings/selling-limits?id=4107&srsltid=AfmBOoq2JyNihLamGpyiQHq...