If i took methadone a couple of days ago, would it be more dangerous then it usually would to take mdma, beacouse of the methadone that still haven't left the body, or what's the deal here?

They don't interact: Both drugs are clearly harmful for different reasons. Methadone is an opiate which can suppress respiration, or lead to overdose. Mdma can have damaging effects on the brain with even a single use.

The big deal: Is that you'll end up dead one day playing around with this poison called mdma and fueling it up with methadone. Stop it!