Any tax-related questions are best addressed to a tax professional or to the IRS. You can find information about reporting and filing requirements for independent contractors at http://www.irs.gov. Our answers can't be considered authoritative, but here is a summary of the situation as we know it.
If you work for a company as an independent contractor, that company may be legally obligated to report your pay to the IRS. Specifically, if you earn $600 or more from a mystery shopping company in a single tax year, that company is supposed to report your earnings to the IRS and issue a 1099-MISC to you; otherwise, they don't have to.
JobSlinger doesn't employ shoppers and isn't involved in whether or not companies send you a 1099. If you want to know if you will be receiving a 1099 form, contact the companies you work for to see what forms you can expect to receive, if any.