I have sent an e-mail campaign and the recipients are responding. I have added myself using a non-affiliated e-mail address to the campaign and I can see my own responses but not those of anyone else on the campaign. Everyone is getting the links and they are filling out the survey to the end and getting the “thank you for completing the survey” message. I can see no responses except my own – which were sent at the same time as the other respondents.
It would be helpful to know what you are using to “see” the responses.
Our process for checking response problems like you are describing is to export the response data (with email campaign info) as a CSV file and then analyze it it MS Excel. The export files have time stamps, response status, and other information that can be helpful in understanding your response data.
Once we have an overview of the responses, it is easier to diagnose problems with other aspects of your survey.