WordPress Widget Not Saving Instance

The problem is your update function. $old_instance is kind of special variable. The simplest is

function update($new_instance, $old_instance) {
    return $new_instance;
}

For the safe

function update($new_instance, $old_instance) {
        $instance = array();
        $instance['name'] = htmlentities($new_instance['name']);
        $instance['divclass'] = htmlentities($new_instance['divclass']);
        $instance['paypal'] = htmlentities($new_instance['paypal']);
        return $instance;
    }