The product is not incredibly inferior, you just bought the wrong size. If you went into the store, bought a shirt, and then went home and found out it didn't fit, you would be disapointed as well. Please don't blame any company for your mistake in buying the wrong size.
Anyways, about your problem with the size. Don't bother with in ear headphones if they don't fit. It seems like common sense. Get a set that goes around the back of your neck, or "street style" headphones. They deliver superior sound better than any earbuds, and stay on relatively well.