Nothing is wrong with the reports. You are correct that you have generated 5 good subscriptions over the course of our partnership. The last good subscription you generated was in November.
The reason you aren't seeing these statistics reflected in the report by time period is because you are most likely searching "by day." When viewing statistics by day, the data is only available for the past 90 days. This is an effort to keep the load time for the reports manageable. If you sort by month instead you will see all of the historical information.