Greetings Rushifell,

I'm very sorry to hear about the issue you're experiencing with the Callback campaign. I'd like to confirm if you're still experiencing this issue at this time?
To help clarify further, as it is indicated in the Callback Campaign F.A.Q "Invitation e-mails will be sent once per day. In the event multiple players send invitations to the same character on the same day, a single e-mail will be sent listing the character names of all inviters." (https://na.finalfantasyxiv.com/lodes...cial/callback/)
Hopefully this information helps and thank you for posting in the Final Fantasy XIV Technical Support Forums