Rejecting verses of the Quran

As salam aleykoum, Recently I get a new job in an Islamic bank elhamdoulilah, then my mom went on the bank website and read the verse of the Quran where it was mention that someone who is involve in riba has to take a notice of war from Allah and His Messenger. Then she said that it was not true, but i don’t know if she was aware that this words are from the Quran. When my mom act like that, most of the time I don’t say anything I rather think before I tell something to avoid saying something wrong about Islam, and to tell her things in a proper way. But this is the first time that she acts like that with something related directly from the Quran, so does the fact that I said anything makes me a disbeliever ? How to advice my mom when she is certain that riba based loan are halal especially to own a property ? Does my silence if I hear someone telling something wrong about Islam (for example what was mention above, or someone who says that birthday are halal…) makes me a disbeliever ? Also you have to know that someone has already told her that riba is a major sin, interest are haram but she seems to not believe in that… this is mainly why I didn’t said anything because I know that she is not ignorant, but maybe to tell her things in a different way to make it really clear to her that this is really really haram BarakallAllah oufikom for your help.