Well i went through your survey project and could see that you had redeployed your survey project 40 different times. In these 40 redeployments, i could see that you added some questions, removed some question and even modified some question types (which i have highlighted in yellow in the attached xlsform below). Those yellow highlights actually did not affect your download with the Export Failed that you see.
Version Comparison:
Version Comparison (Export Failed).xlsx (19.3 KB)
The problem that caused Export Failed was when you first deployed your xlsform (or say your survey project) with a repeat group and then submitting the data with the repeat group to the server but later removed those repeat groups (in your recent redeployment).
Solution:
You should be able to download your data, if you once again group the questions as repeat group and name the group as repeat_ben as they were grouped and named before.
