I have managed ESOPs for companies. Many have come to me saying xyz was promised. The only reason they got what was promised orally if they are still relevant in the plan. If you can still contribute to the future growth. Else nada ; didn't promise; ignore him/her till they leave.
No founder gives away equity generously. If they are saying that then they are lying or stupid. There's only 100% of equity. Limited resource. So they are very careful in doling it out and they should be.
What should you do? Get what is pormosed for in writing, in contract immediately. Don't wait. Or keep having leverage/relevance and hope for the best.