Why dont take they me serious?

It's difficult to get people to see things they don't want to see. My only advice is similar to advice I've given certain friends I've had who, for a variety of reasons, have met with consistent disapproval from their families: Get out from under it, as best you can. Don't look for validation, approval, and certainly not support from your family. It sucks, having to distance yourself emotionally from them, but it might be the way to make things better.

I know a woman who is fairly accomplished in life. But every great thing she does is belittled or marginalized by her family, even though many other people in her life (including me) are impressed, and proud of her. Still, she's cried to me that she feels awful because her family doesn't respect her. I asked her why she's allowing one specific group of people to dictate her worth. The world is a big place, and there are some (at least a few) enlightened people out there who make value judgements based on merit.

Family is important, but sometimes you have to distance yourself, if the situation is toxic.

Just my $0.02...

It doesn't have to be that dramatic (unless you really feel that way). It's just about realizing that you probably can't change how they are, which in itself is indication that they're not open-minded enough for you to really be placing too much weight in their behavior.

It's more about emotionally distancing yourself. If you DO have other people in your life who respect you for who you are and what you can do, it can help to turn your thoughts towards them. It isn't the "ultimate" solution, and it goes against the platitudes about not caring what anyone else (at all) thinks. But in my experience, that's unrealistic too. It leads to a feeling that you're all alone, and the whole world is against you. Instead, I tell myself that I have friends in my life who see beneath the surface details of what I look like, and value the person I am, so I don't care that certain people who are close to me just can't do that.

I guess you just have to relate to certain people with an arms-length approach. You can talk to them, see them, do things with them, but make it so you aren't relying on them, and definitely aren't caring how they disrespect you. It's a tough thing to manage, but it might be an approach that doesn't just throw everything out the window. Just taking a few subtle, stealthy steps back...

Edit: I say this, because you've indicated that you've confronted your family already, and tried to get them to see what they're doing, but they're refusing to accept it. If it's been that harsh, then it probably isn't worth it to keep pushing. If they really value you at all, and they start to sense that you're becoming more distant, they might wake up and realize what's really happening. Don't count on it though, but sometimes, certain people actually heed that wake-up call.