international packages need to be signed for.. if you weren't home or your postman is too lazy/in a rush to go to your door they will leave a slip. just go pick up your stuff
if it was domestic and it didn't fit the box then go pick it up
the bad news is if you used a fake name and they look at your ID and see you aren't the same person they have the discretion to deny giving you the package. make sure you are EXTRA nice to the person there when you go up there, maybe go right when they open before another customer pisses them off.
i've been in this situation before and it wasn't even steroids, it was another package and they would not give it to me cause the name on the package was not mine, even though the address matched my ID. after pleading with the lady for 5 minutes she finally gave it up, you just have to know how to talk to people