A Proper Thank You For Comingwedding What Is A Proper Thank You For A Successful Business Referral? Dinner? Thank You Note?

What is a proper thank you for a successful business referral? Dinner? Thank you note? - a proper thank you for comingwedding

My friend directed me to a client who needs help in an area that his company tried to manage. After winning company, your colleague told me that I owe my friend for dinner in the application. I owe nothing to my friend? The compliance of their performance is above their level of service. I have no problem with him to dinner, but I do not feel like a gift, both the expansion of the services they can offer to their customers.