If you go to your payments tab on the website, it will tell you about how long it takes each MSP you've completed a job for to release payment. For shops that I've completed, some have taken less than a month, while others take a month or more.
For the Mission Scanner app, the MSP should provide you with your login information.
It's possible that you have requested the shop, but have not been officially assigned yet. You can see a list of pending requests if you go under the "Requests" tab on the iSS home page. Some shops are available for self-assign, while other requests need to be approved by the MSP.
There's a self-assign limit, but you can get more than 2 jobs if you apply and are assigned by a scheduler.
I completely agree with being professional and following directions. However, I feel like no matter how much you prepare or stick to a scenario, once in a while something unexpected happens that you have to improvise a response to. That's when I feel like things can get a little silly.
You can check on payments by going to the "Payments" tab on the iSS website. If you then filter by pending payments, you can see what's owed to you and how long it typically takes an MSP to pay. There should also be a phone number and e-mail address you can reach out to regarding payments. I would personally be patient for a while and contact them if the time for payment has exceeded the listed average for that provider. For most MSPs, I believe you should expect a payment through PayPal.
I've done a number of these and would suggest starting right when the store opens to give yourself enough time and gauge how long it takes. You will get significantly faster at doing the scans if you do multiple shops. While these kind of shops are time-consuming, I think they are on the more simple end of the spectrum of assignments. I would not worry about not doing it right, just pay attention to the training materials. The MSP is also very responsive and you can reach out with questions if you are unsure of something while doing the shop. They may also reach out to you to make sure everything is going well and you don't have any questions. This was my experience, at least.
If you go under "Update Extended Profile," there is a spot there where you can see and edit your PayPal e-mail address.
Looking under "Pending" rather than "Paid" in the payments are may be helpful to you, too. How long it will take to get paid depends on the MSP, but estimated time frames are listed.
As far as I know, you will just get a referral badge if you refer enough people to the site.