Sounds like a slippery slope to tangle with. I personally have dealt with “sharks in the water” amongst the fitness industry. You can ask for compensation but, if they weren’t willing to make good on their first promise, you may be dealing with a “shark.” As far as I am aware, there is no industry standard. You would be well advised to make your clients aware that you wish to recieve their referrals directly. Use business cards so they will only have your name in mind. Might be best just taking this one on the chin and moving on. Believe me when I say, there are plenty of potential clients to go around.