K.S.
You may be trying TOO HARD and worrying too much about it. People are busy and you shouldn't take it personally. If you constantly call you could become a nuisance and people will avoid you. Just take your kids out (playground, park, etc) and let them enjoy themselves. There are kids there that they can play with and they'll be able to meet all sorts of kids, not just the ones in their neighborhood. Your whole family doesn't need to bond with your child's playmate and kids aren't too concerned about that. You can also check your local church/community center to see if there are established play groups in your area.
Good luck.