Consignment law

I am a South African teddy bear artist. Last year while in London, I handed 3 bears over to Diane Pawuk of Bear Paths, Ohio to sell on consignment. During the year she sold 2 of them. Each time it took me months to get my money and although we had agreed on 20% commission, she took nearly 25%, citing the PayPal charges she had incurred. She had also agreed to return the 3rd bear to London, but then changed her mind and refused, insisting on mailing it back to South Africa. By doing that, I won't get it in time to sell it at the London show this year. She now says she has mailed it but has provided no proof of mailing. She has also threatened to blacklist me among other show promoters and shops because I insisted on payment. Is there anything that I can do here?