lclemons - I haven't done any vitamin shops this year, but I want to make two suggestions so you don't run into this problem again in the future.
You need to have a spreadsheet which includes a minimum of information on the shop date, the client's name, the mystery shopping company, the job number, the fee, the reimbursement, and the mileage. This should be posted with each shop before you do the shop, and the mileage should be posted the night you complete the report. This information will be useful for taxes and for looking for an individual shop.
Every MSP I have ever signed up with has sent me an acknowledgement email, usually including my log on information as well as contact information for the MSP. In my email, I set up a folder for each MSP and at a minimum it includes this email. I also save all bonus offers etc. to this email folder as well as any regular offers including a scheduler name or any other information I want to capture.
If you will develop a comprehensive spreadsheet and a good email file system on your MSPs, your reward will be resource information at your fingertips.
Mary Davis Nowell. Based close to Fort Worth. Shopping Interstate 20 east and west, Interstate 35 north and south.