Breach of verbal contract - is there a solution?

My product has been received by the buyer, but payment not yet made or accepted. Initial payment was to be in kind for similar product, but since buyer has misrepresented method of their business practices, and have been exposed recently of indulging in unfair competition with other providers, I would like to either recall my product or be paid in cash for it. The exchange was not on written contract but decided based on trust which has been broken. Although never written down on a contract, can a verbal understanding hold its ground?
Ruth