Do you have a link? A few companies call themselves Shopper Service or Services so it is hard to tell whether the one you mention is one of those or something just masquerading as one of them.
I was able to obtain more info about this company by checking on volition. The name is Shopper Services. They are one of those companies that charge an initial $1.95 fee and then $20 per month thereafter for accessing their site for jobs. They charge for what Jobslinger does for free. I saw an ad in my local paper and was wondering about them. So I don't recommend using them since you'd be paying to look for jobs you can obtain for free. Thanks for the response though.