So, for any of those shops that are on the 'magic" app, (with the exception of the shop with the alphabet letter in the round thing), this what I do:
At the site, I check in to unlock the report with my cell phone. If the site has no service, check in as close to possible as soon as you see the signal return. Report the problem in the report.
For me, I use my digital camera and download the photos into my ever present laptop.
I always create a worksheet for each site and brand. It is individualized for the particular brand and what the MSC asks. The receipts are stapled to that sheet.
Prior to leaving the site, I rename and view the photos on my laptop. I check off each photo required on my worksheet and add the needed data that each site wants (type of shirt that the employee wore, their name, etc, etc)
For the sites with the alphabet letter, I take photos with my cell phone (on silent) and download those into my laptop.
When I return home, I file the reports with my laptop. There has never been a problem
On my worksheet, I also input specifics about the particular shop immediately upon taking the shop. Most important is the end date and time that I am obligated to report the shop before flaking. That is very important for those shops that only have an 8 hour reporting window.
It pays to be organized for a multitude of reasons.