As we first reported, Brittney Jones posted the sweater last month with a starting price of $500. We're told the bidding got up to $21,000 with just a few hours to go ... when it was mysteriously pulled.

Brit got an email from eBay saying it was pulled because it didn't have "a cleaning disclaimer" -- a must for all used clothing sales. She then got another email a week later saying her listing has been restored ... so now she's trying once again to sell the sweater.

Seems Brittney is having a harder time getting rid of that sweater than Ashton is getting rid of her.