The CPI is the "contractor payment invoice." Yes, you must submit it. If you don't, you will get paid still. However if you do not do this within the time frame they want and do not submit one a few times, they have been known to deactivate the shopper for this "sin of omission."
If you already submitted the shop report, you no longer have access to the original CPI. They require that you print and/or electronically save the file before the report is completed. So, you have to submit a replacement CPI. It requires that you word process the details into their text file and upload that.
You can find the replacement at the Help section of their shopper site.
I am not sure about the tolls and parking as I never have had to pay any for my shops for them.
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“Lying in bed would be an altogether perfect and supreme experience if only one had a colored pencil long enough to draw on the ceiling."
~Gilbert K. Chesterton