They may make good on it next time they see you, but I'm guessing they spent that 40 minutes reading the terms of the site and went "nope". It's totally against the rules. Not only by being a bathroom fetish thing, but also we are not allowed to use any devices or "toys" that are not specifically made to be sex toys. So no hair brushes, random objects, etc and I think enema equipment might fall under they umbrella. Really, we aren't even allowed to cam when we are on our periods in case a little blood shows, nevermind performing an enema on cam. The couple should have known this and said no right away, but they may have genuinely intended to follow through. On the other hand, they may have been annoyed by you asking. You just won't know unless you can ask them.
I wouldn't hold your breath for a refund. 200 is not a lot to most performers and IMO, not nearly enough for what you were asking, since they could easily be banned for doing it. I personally have had a couple incidents where people have tipped 10-20 tk for something (like a pm) and then I had to go. They show up later trying to make good on it and I'm like, "Seriously?!" Tips are not in exchange for anything. Tip menus are just guidelines for what the minimum amount my be to inspire a model to fulfill a certain request. Any time you nickel and dime a cam model by asking, "Will you do x for x amount of tokens?" You are violating site rules, as well as insulting the model and sucking all of the fun out of it for them. In the future, take them private and ask beforehand if they are open to your request. If you are really against going pvt, ask about their guidelines and then tip a fair amount, and THEN make your request. Yes, there is a risk that they will not do it, but if you have tipped a fair amount, and they have already stated they are open to your request, you will generally find a lot more generosity from the models when you are classy enough to tip and include your request along with the tip, instead of trying to get them to agree to a price ahead of time which again, violates the rules of the site.