A number of factors could have contributed to not receiving payment for your concept. Here are some potential reasons and areas you might want to explore:
Contractual Agreement: Review any contractual agreements or terms of service related to your work. If you didn’t have a formal contract in place, this might be a key issue. Contracts should clearly define compensation, terms, and expectations from both parties.
Ownership Clarity: Ensure there was a mutual understanding of ownership rights. Sometimes, concepts are shared in collaborative environments where ownership and compensation aren’t clearly defined. This could lead to misunderstandings about who is owed what.
Market Demand and Value Proposition: Consider whether the concept itself was perceived as valuable by the intended audience or client. Evaluate whether it aligned well with market needs or had a clear value proposition that justifies compensation.
Client Relationship and Trust: Reflect on the relationship you have with the client or entity that your concept was presented to. Building trust and professional relationships can often influence compensation negotiations.
Presentation and Communication: How was the concept presented? Effective communication of your idea and its potential benefits can play a crucial role in securing payment. Ensure that your presentations clearly illustrate the concept’s value.
Monetization Strategy: Examine if there was a lacking or ineffective monetization strategy. Even a great concept needs a clear path to generate revenue or benefits for those who might pay for it.
Industry Standards: Research industry norms regarding payment for concepts, especially if you’re entering a new field. Sometimes, concepts are not immediately compensated until they’ve proven potential for success.
Feedback and Iteration: Reach out for feedback. Sometimes, understanding why payment wasn’t received can provide insights into how to refine the concept further or address barriers to its acceptance.

To address the situation, you might want to open a dialogue with any involved parties to understand their perspective and get clarity on why compensation was withheld. Consider these aspects for future engagements to ideally position your work for appropriate recognition and payment.