How can I check my mails in Google?

I sent $39.97 to a company called WAH for a "job" of Data Entry and they made me open an account in Google. I don't know my name there and they say that I am receiving replies from them in my mail from Google. I don't know how to check that. I am confussed because I just put my regular mail here in Yahoo and another pword and that is the way how I can enter to my order in Goggle but that's it. Please help me. Thank You.