Did you tell her marriage was has a transactional expectation as well...

> She mentioned that that was a transactional gift and I gifted her the shoes to get something in return

Actually if she kept the sneakers without you getting your side of a transaction, that breaks the transactional contract...reclaim those shoes. had she modeled said shoes, you would no longer have any legal standing to reclaim the merchandise, as she would have completed her end of the transaction concluding the business and legally laying claim to said shoes. Make sure your marriage contract is solid. This one seems like they want to rig the property in her favor, through legal trickery.