What to do about my mastiff?

We have a 10 week old mastiff and she does not listen very well. We would love to get rid of this while she is little. She will not come when called, she acts as though we are not even there. Also she is terrified of me for some reason, and I have never hit her or even really been mean to her, except when she does something wrong (just a stern voice, nothing serious) . She also will not walk on a leash at all, she just sits there and is a big pain. Anybody have any idea what to do with her?