Depends on your platform. The more "online", you are, the shorter the patience from your customer. On emails, I am thrilled, if I get answer within 30 minutes. Happy within a couple of hours. Unhappy, if I don't get response on the same day; I will assume, you have forgotten about me.
I think all experience from marketing and sales is, that time is of the essence. So the sooner you solve a problem, the better.
I hope this answers your question. If not, feel free to set up a call to talk further.