Hello and thank you for entrusting me to assist you. My name is ***** ***** I will do everything I can to answer your question.
I am very sorry about this. Unfortunately, no law requires employers to be fair or reasonable when it comes to the management of their employees. So, it is perfectly legal for an employer to simply decide not to promote someone based on the belief they do not possess the necessary skills, are confrontational, or whatever else, even if this is completely untrue and undocumented. It is only illegal for an employer to engage in this sort of conduct if their reason is the employee's race, religion, disability or some other legally protected trait. Here, that does not appear to be the case, because although you are African American, so to is the HR rep that attempted to persuade you to resign. You also have not stated any facts which suggest an intent to discriminate against you because of your race.
You would likely need compelling evidence that this all has to do with the fact you are African American in order to have a claim. Otherwise, I'm afraid you work for an employer who is unfair, who has without good reason decided you are not a good fit for advancement within the company, but who is not violating the law.
This sometimes happens, and all an employee can do in that situation is move on to a better job with more potential for growth. Most employees over the course of their career work a job that is a dead end in this respect. Ultimately, you cannot force your employer to promote you or force them to believe you are qualified for a promotion. As unfair as it is, this is just the nature of office politics and the best recourse is usually just to move on.
I hope that you find this information helpful and am genuinely sorry if it is not what you were hoping to hear. Please do not hesitate to let me know if you have any questions or concerns regarding the above and I will be more than happy to assist you further.
If you do not require any further assistance, please be so kind as to provide a positive rating of my service so that I may receive credit for assisting you. Very best wishes moving forward.