Lab tests and laws regarding methadrone

I had a friend send me some methadrone in the mail. The package started leaking as it was being put in the mailbox. Methadrone is currently unscheduled. They called the police and a federal officer and a county officer came to my house. They said they wouldnt press charges on me unless theres anything but what i said or think is in there. I told them everything I knew about it. They said the dog didnt really pick up on it. They said they were sending it to the lab. The county officer and federal officer said that if there was something else in it they would bust down my door with a squad. I am scared. How long do lab tests usually take? And if you have any other information please let me know