(Full disclosure - I'm associated with Zoho).
I'm not sure exactly what your scenario is, but if you want to have a schedule people can choose from, then take payment for some appointment or something like that,you might want to look at Zoho Creator. Not sure what part of Zoho you're using right now (we have lots!), but Zoho Creator (and Zoho Invoice) have the ability to process payments. And then of course Zoho Creator has all the scripting abilities, etc.
Let me know what you want to do and maybe I can point you in the right direction.