Not working with select/dropdown input fields

I’m finding that the plugin is not passing data from a select/dropdown input field. For example, on the form I have two dates and times for the user to select from:
– March 1, 2019 at 11am
– March 1, 2019 at 6pm
I have set the field to use ts_Wkspdate as the custom field tag in both CF7 and Sendy. And in Sendy’s custom fields section for the autoresponder campaign, I set ts_Wkspdate as a text data type, not a date.

But when I look at my CSV file for the list, I find that the ts_Wkspdate column is empty. Thus I cannot insert this date + time data in an email via a personalization tag [ts_Wkspdate,fallback=March 1st] — I have to use fallback instead, but that’s not very specific because time is not included.

Any ideas on how to get options in a dropdown menu to pass to Sendy? Who has been able to do this? It seems like this functionality should be baked in, but either the plugin or Sendy is not supporting this type of input.