If your iMessage number is incorrect the day after your number has switched over to Honest, please call another phone number (or get someone to call you) to test that your number has successfully transferred.
Step-by-step guide 🔢
Please attempt each step one by one:
Go to Settings > Apps > Messages and toggle iMessage off.
Go to Settings > Apps > Phone > My Number and manually change it to your correct number
If the steps above don't work, you'll need to reset your network settings, using the help here