Treat it as science, and start the process by attempting to falsify the initial hypothesis of pure r-isomer.
This could be done by extracting the MDMA -- testing for purity by melting point, and then using a polarimeter, Mosher's process, or some other low cost but scientifically effective process.
If we made the free base from the purified MDMA -- and then used r-tartaric acid (chiral) to precipitate MDMA-tartrate, if it was only 1 isomer it would all precipitate out, OR NONE WOULD -- if the free-base partially precipitated -- racemic
The next steps could be done in any order. Simply because GCMS says it's MDMA -- does not mean it actually IS MDMA.
Regardless of protestation to the contrary, skeletal, functional, and geometric isomers (that have many functional groups in common) can be very difficult to differentiate with standard GCMS.
5-Methyl MDA and 6-Methyl MDA are both isomers (not stereo) of MDMA , as is 2,3 MDMA
The methyl MDA compounds have a profile of effect that is similar to what is reported.
Just because something is pressed the same -- does not mean it's the same batch.
Le Junk identified that the "mongy" MDMA made him cracked out and high for 2 days -- that is not what r-MDMA does, it has a very slight action (+1) even at 200 mg that is gone in 6 hours
5-APB or 6-APB however, are 2 compounds that are remarkably identical to MDMA in effect -- some people say better a 200 mg dose of an APB would probably make you feel high for 2 days (75 mg can rock you for 12 hours)
the mongy effects sound alot like higher doses of 5-Methyl or 6-Methyl MDA -- wonder if they look like MDMA to a GCMS
They could be slightly different but in the sample noise