How do we collect telephone numbers which start with a leading zero?

[Kal_Lam]

OK, maybe you could follow this post to see how to reference a value used previously in a constraint_message:

About using logic

You could do the same as outlined in the image shared below: In the survey tab of your xlsform: [Image 1] Data entry screen as seen in Enketo: (when a wrong entry is made) [Image 2] Data entry screen as seen in Enketo: (when a correct entry is made) [Image 3] Reference xlsform: Bank.xlsx (10.4 KB)