pawn shop sold my item

I took a loan out on my Artsy Louis Vuitton purse . On December 22, 2017 I paid for this item to have a extension for 30days. During that time one of the pawn shop employee put my item out for sale before the 30 days period was up . I was informed my item was sold. Because the employee who took my money for the extension enter the money under the wrong account leaving my account to become available to sale . What rights I have at this point I would like for them to replace my item . Do I have to paid for the original loan. I paid 1600 for this item under new conditions but in order for me to replace this item just like I gave to them will cost my all most retail price. He has offered to replace my item with other Louis Vuitton in their possession but this item don't value the same . I need help understanding what I can do in order to replacing what they sold .