I am in a fix right now. Somehow two raccoons have got into the yard and they are destroying my garden by tunneling holes in the soil

I tried getting rid of them by trapping but they always seem to miss the bait or are too clever enough to avoid it. I thought about calling some humane wildlife removal services (
http://removethewild.com/ ) because I don't want them to be killed. What do I do to make sure that they don't get into the house? I have heard that using mothballs and anti-animal spray would work. If anybody could share any suggestions on this, it would be great.