How can I access live chat support? I have a suspicious transaction that I need help with.

I am not a techie guru - I inherited these duties when I started here a few months ago.  So I basically do what I have been told by the person before me.  We now have a very suspicious transaction that came through ecommerce, and I would like to have someone help me figure it out.  But for the life of me I can't figure out how to actually contact anyone in support.  Can someone please help?????