I'm looking to install Chat on my website, I know there are many third parties out there, probably the most important thing is it must be reliable (I don't need downtime) and professional.

options I'd like:
call the chat action with a button (Xara easy)
insert the button on a sticky at the side (Xara easy)
pops up on a page after so many seconds of user inactivity ...."would you like help?" (a server / third party capability I think)

any advice appreciated. thanks