My Ibotta email address is not with Ibotta, either. But text messages are based on your phone number. If you signed up for text alerts, you would have entered your phone number.
If you are not getting emails, that's another story. I think I get two or three emails a day from Ibotta. Every time I submit a receipt, I get an email. If you don't get those, you may have accidentally blocked them or sent them to Spam. Check your spam folder or your trash folder.
