The Messenger of Allaah (peace and blessings of Allaah be upon him) said: “A previously-married woman should not be married without being consulted, and a virgin should not be married without asking her permission.” They said, “O Messenger of Allaah, how is her permission given?” He said, “By her silence.” (Reported by al-Bukhaari, 6455)
So if she said No, it's a no. Her silence is a yes.
‘Aa’ishah reported that a girl came to her and said, “My father married me to his brother’s son in order to raise his social standing, and I did not want this marriage [I was forced into it].” ‘Aa’ishah said, “Sit here until the Prophet (peace and blessings of Allaah be upon him) comes. The Messenger of Allaah (peace and blessings of Allaah be upon him) came and she told him about the girl. The Prophet (peace and blessings of Allaah be upon him) sent for her father, then he gave the girl the choice of what to do. She said, “O Messenger of Allaah, I have accepted what my father did, but I wanted to prove something to other women.” (Reported by al-Nisaa’i, 3217)
You need the permission of both her and the wali in order for it to be halal.