1. Do you mean renegotiating the Withdrawal Agreement? If they say yes, then:
2. Why do you think everyone in the EU is lying?
3. What does voting against a deal you can't renegotiate achieve? If all you want to renegotiate is the (non-binding) political declaration, they why not vote this through and focus your attention on getting a better deal in transition?
Put your cards on the table:
1. Exit with this deal
2. Exit with no deal
3. Push for a 2nd ref
4. Push for A50 extension and a GE
The public deserve clarity.
5. Exit with a softer Brexit than this deal (keep single market, permanent customs union etc). I can see the EU accepting that, potentially - but if that's the strategy, say so, and say how you'll get EU to accept it.