I have a six and a half old Great Pyrenees/Golden Retriever pup.She minds well,sit,lay down,will even sit and wait while I put her leash on. But she will not come when you want her to. I've tried treats,everything,but to no avail.She'll run around and play until she's good and ready and only then will she come to me. I'm too sick to chase her around while she plays her game. What can I do?