Had the same problem. Unfortunately the MSP is on the West coast, hours behind me. Left a msg and they never called back, but since I had committed to a date, I went anyway. Wasted 3 hours of my time after my " contract " had been accepted. When do you think I should have been contacted regarding (not) getting the gig?
This is pretty much the end of my experience with this company. I also find that the same restaurants are just using this to get customers, as the bill always seems higher than the reimbursement and compensation.
You should make sure to always try contacting the MSP at their official company email (not the individual scheduler's email) and you can also call the company number and leave a voicemail if you are not getting a response. If you don't know some if this info (their email, phone number), you can open a support ticket for iSecretShop, and you'll get that information pretty quickly.
Finally, do not proceed with the shop until you hear back from the schedulers, and if they give you a late reply, you can always ask to reschedule.
As for the restaurant shops - I've had mostly different experiences, as the bill is usually about slightly lower than the reimbursement amount, and the tip makes it go just a few dollars over - it all depends on what you're having, how many guests do you bring to the shop, etc...
I've found that if I go onto a restaurant's website before my shop, I can plan what I want to eat while still keeping the bill within my reimbursement amount. I just add the cost of the items I will order and calculate my tip based on what the bill total should be and.....voila.....I don't overspend if I'm wanting to stay within my reimbursement amount! Most restaurants now have their menu available online.