My dog was like that when I got him from the pound. From the cage, he wanted love, but when we ed it, he got scared. The more I tried, the more he ran. So I ignored him. I left him food as usual but did things in front of him that would seem fun to him, like he wasn't there. Bounce a ball to myself, sing a song kinda loud (heard dogs like people singing, makes them calm) and leave the house with his leash and not him. After about a month, he'd be on the receiving end of that ball.... Weaving between my legs while I was talking (cuz of the singing) and he finally wanted to see where the leash was going. But then each of those steps has to go slowly. He may not want to return the ball at first, it may be more fun to "take it from you" let him learn to fetch or whatever, try not to TEACH it as much, if he's the timid type. He'll get used to you, had my lab for 13 years now.