Hey @nimfafrance ,
Before clicking ”Complete” you might need to run a QA check. So, In Phrase’s CAT web editor (where you worked on your translation), look at the pane on the right; there are several tabs there: “CAT”, “Search”, “QA”, “Changes”, “More”, “Comments”, “LQA”. Click on “QA”, then on “Run”. There will be a list of errors that you need to check. Some of them might be false positives (correct segments wrongly flagged as errors - example here) in which case you just click “Ignore”. After you finish with all the errors flagged during the QA check, you can click “Complete” and you will receive an email about successfully submitting your task.
You can also go to your TWB platform profile, go to the tab “Claimed tasks” and find your task. The last line in the information about it is “Discuss this task on TWB Community”. Click that link and you will be redirected to the project’s TWB Community page, where you can discuss with other translators and revisers involved in the project, as well as the Project Manager. From there, you can also find out the email address of the PM, and contact them about your problem, they are quick to answer and happy to help 
Happy translating!
Elena