If you have any reason to believe that the treatment that you're experiencing is due to discrimination based on a protected characteristic (such as race, gender, national origin, or ethnicity) you should file a complaint with the Department of Fair Employment and Housing.
You can do so using the information available online here:
The DFEH will investigate the claim on your behalf and either file suit on your behalf or issue you a right to sue letter.
Regardless of whether you believe you're being discriminated against or not, you should definitely not
quit your job. If you stay on the job, you will be eligible for unemployment benefits if you are terminated, as long as your employer cannot prove that you were terminated for cause (which seems unlikely given the facts here).
Although you could potentially be eligible for unemployment benfits if you were to quit your job, it is unlikely, since you would need to prove objectively that any other reasonable employee who wanted to stay employed would also leave his or her job in the same circumstances.
I find it odd that you would not be treated differently due to your increase in sales, but it also could just be necessary that you coninue to be persistent, and try not to leve the lack of positive feedback damage your morale.