Wow, sorry to hear of your problems
. I am definetely the alpha and have no problems with my pup. She will sometimes make a little strange sound (not really a growl) and bark when I get her brush or sweater out but it's all play. She has the classic rear up front paws down position when she does it and will bite on the rare occasion but never with any pressure at all. Can you talk to the breeder? My pup comes from a show breeder but the are very particular on temperment stake their name on it.
Good luck, hopefully someone can give you some good advice.