Will I be punished for not helping my friend who lost her money after I introduced her to a person who swindled her, even though my intention was to help her, and she blamed me and spoke ill of me?

It is not permissible, Islamically, for women and men to socialize and form friendships except out of necessity and within strict guidelines, as it is a gateway to fitna (temptation/strife). As for paying money to someone to accomplish tasks, if it is to interfere with public interests and favor some over others, then it is a forbidden bribe. However, if it is to obtain a right or a permissible job opportunity, and it cannot be obtained except by paying this money, then there is no harm in it for the giver. It is not considered a bribe on their part, even if it is a bribe for the recipient. The ruling on what you have done depends on this: if paying the money was forbidden, then it is a sin for everyone because it is cooperation in sin and aggression. But if it was permissible, then there is no sin upon you for the loss of the money. In all cases, you are not responsible for guaranteeing the money as long as your role was limited to delivering it.