Hi, I'm new here and I really need your help. We got our 14 months old pup (english cocker spaniel), two months ago. They said they were giving him away, because one of the owners was on a wheelchair and unable to take care of him when home alone. When we came to get the dog, we saw the guy on a wheelchair, so we believed that this was a genuine reason. The dog was sweet, playful, we were able to pick him up and everything. Fisrt days at home he was great with everyone, but then the problems started. He wasn't trained at all before, so we started basic training which he picked up on very quickly (sit, paw, lay down, come, leave). But when the mailman passes our house or enters, or any other motorcycle, bike, runnin person... he goes crazy. He barks, grolws and gets overstimulated. He doesn't listen to any commands, barks at us and tries to redirect his 'aggression' towards us. When I wanted to pull him back from the mailman, affraid that he was gonna lunge at him, he turned around and snarled and growled at me. Thankfully he didn't bite, but he could've. Is there anyone who could help me with this? His previous owners obviously hid te real reason they gave him away, but I really love him already and don't want to give him away, because he can be so so sweet and loving otherwise. And changing homes for the rest of his live feels unacceptable to be, but I don't want to live in fear of him hurting anyone in my familly. Please help, thank you.