Due to the way RotoTracker detects duplicates, this will mangle your data.
RotoTracker does not support importing data from multiple user accounts from the same Daily Fantasy Sports site. It won't throw an error, however your data will be inaccurate.
When you import a file, RotoTracker needs to work out which contests are new and which were already imported. If you upload data from multiple users who entered the same contest, this will confuse RotoTracker and cause data to be skipped over.
Right now the only option is to maintain multiple RotoTracker accounts. If you are a plus user, contact support and we can offer you a deal on additional plus accounts, if that is something you need.
You need to delete the offending CSV files, then re-upload the data. Its probably best to delete all uploads back to before the date when you imported the extra user. See this FAQ on how to delete data.
If you can't find the answer to your question, or you have found a bug, have a suggestion or have feedback, please don't hesitate to contact us! You can email us directly at support@rototracker.com and we'll get back to you!