Thank you for reaching out to the Constant Contact Community. It's my pleasure to assist this weekend.
I'm very sorry to hear that you are encountering an issue with uploading the custom information. If you can send us an email to social_support(at)constantcontact(dot)com with your username, the spreadsheet, and the name of the list you are trying to add it to as well as a reference to this post and we will look into the problem.
Thank you for choosing Constant Contact. Have a great weekend.
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