Can I get some advice...?

Next time,
If I were armed with a signed agreement and had already signed the ads,
it would be far less costly and troublesome to get the agreement enforced legaly by a small claims court.
Would take about 1 hour to do and cost $85, (in my area)

Don states that he gets $20 per room profit from this program, so any more than a 10 room hotel I would most certainly get the judgement in small claims court at a cost of 1 hour of time and a $85 filing fee.

You should consider this next time a person doesn't stick to their signed word.
Will save you face with current advertisers and you will get paid for the service that you provided.
Best of luck,
Jason