I shopped for them for years and I recently left and asked them to remove me from their list of shoppers.
*Shop requirements would change AFTER the shop was completed. Ex: The shop instructions said to shop between 9am and 11am and you did, then you would be told it was supposed to be 2pm - 4 pm and you did the wrong time. Even when you pointed out what the assignment said, you were still wrong, but they would "accept it this time as a courtesy".
*Completed shops would disappear. They, like other companies, have a place where you can see shops assigned to you - whether they're done, pending, waiting for payment, or done. Toward the end, I was having problems where I would go to check the status of a completed shop and it would be gone. A couple of times, I did airport rotations, and ALL of the airport jobs disappeared. When I questioned it, I got a nasty email or completely ignored. A couple of times, there were over $300 pending for that month and they would all disappear and I sure wasn't going to just let go of that money. They always claimed it was a system problem or an IT problem, but I found it interesting that the cheap fast food shops never did this - only the multiple airport jobs.
*Payments were sometimes late, but when I would question it (days past the due date), I would get told that most months they paid me early, so I had no reason to complain.
*They wasted my time asking me to get an airport badge, giving me the wrong paperwork, asking me to come to their office to resolve during a certain date/time and nobody was there, and then telling me that they didn't need airport shoppers after all. I had to take time off work to go to the airport, pay parking, etc and then the form was filled out wrong or they gave me the wrong one entirely. The few times I was in their office, they tried to sell me a security system (apparently their other business?).
*When I would email or leave a voicemail for my one and only contact and get no response for several days, I would follow up with the manager... then, my contact would send me a nasty email about how I had no right to email the manager for answers when she received my email and was going to answer it.
At the end of the day, yes I did get paid for my shops, but I had to keep track of it and chase them down frequently. It just wasn't worth it to me, but maybe it is to someone else. I really loved doing the airport shops, and I was sad to leave, but I felt I had to. I hope when the airport job comes up for bid again that another company will pick it up.