To find out which customers have decided to cancel the automatic renewal of their membership, click on Reports -> Marketing -> CRM -> and select "cancellation of automatic renewal" in the Outcome field. 

Then in the "Creation Date" field, select the time range.

At this point you can click on Add or if you need to know who cancelled the automatic renewal of a specific multipack, you can click on the "Multipack" filter and then select the desired multipack, then click on Add to find out the results.