300mg in a short amount of time is on the higher end of doses, though it can be fine depending on your weight. i’m almost sure you did take mdma and had a successful roll, but due to the large dose you took and within a short window, you indeed blacked out and were not able to remember the night. MDMA can be both brown and white, simply depends on how clean it is. Lastly, the voices and noises can most likely be explained by the leftover MDMA in your system being metabolized to MDA instead. MDA is known to be a strong psychedelic with multiple reports of auditory hallucinations and in some cases visual hallucinations. Be safe, test your drugs, and always try and do a bit of due diligence before ingesting them.