I'm not an expert, but I do know one reason it's recommended that people get a male and female, rather than 2 males or 2 females, is to avoid the problem with status. Remember, all dogs are 98% grey wolf. They belong in a pack and everyone has their place. You are the pack leaders, so they need to work out their place in the pecking order. They'll fight until one backs down.

Also, they're puppies. They're going to play. Have you had this breed mix before? It may be a characteristic of the breed. I wouldn't expect puppies to be calm and obedient. Are you taking them to puppy school?

ETA - one reason may be they were too young to be away from their mother, who teaches them a lot of this stuff. Puppies shouldn't be away from their mother before they're 8-12 weeks. Did you meet the parents?