This is an issue we had recently. The email said:
"We aren’t tracking any numbers. I’m not sure why. Attached is the source code of the thank you page where the counters are. They are located in four external js files:....."
So anytime you have this issue, check the following things in this order - and the problem was one of them, I won't tell you which

#1 - Is the counter on the page we want to track?
--Please, PLEASE verify this first. Someone must make sure the customer put the counter on the appropriate page.
--If we ASSUME it is there, we are setting ourselves up for failure.
#2 - Is the counter in question associated with the correct subject?
--If the counter is not associated with the subject, the action from that counter will be ignored.
--Go to the Change activity tracking link in the Subject level and in the Counter tab, select the counter.
#3 - Is the counter on a page in a different domain than the test page?
--If pages are switching domain, you will need to use cross-domain cookies.
--Go to the Change activity tracking link in the Subject level and in the Cookie tab, select cross-domain for the cookie domain.
#4 - Are the reports up to date?
--Sometimes there is a lag in our reporting.
---Even though the reports say "* Today's metrics include activity through 10:40 AM EST" at 10:44 EST, the numbers may still not be up to that time.
---Large volumes of traffic result in delay of data migrating to our Database
--To see latest times, set up a Daily report with 5 minute increments. To do that:
---Go to the Wave of interest. On the left side, Under the header that says Reports, click on the view link and select daily
---Now you are in the wave, on the left click Customize..., and under the General tab, in the Time Period select, choose Daily in 5 minute intervals and click OK.
---Scroll to the bottom of the report and see the last 5 minute interval with an action from that counter, or any activity in general