Closing date passed and never extended - Contract void?

[Ben Kirchner]

(This deal is happening in the state of Missouri)

- Agreed upon closing date was 7/12/21

- Addendum on contract: "$10,000 CREDIT to be given, in lieu of repairs, and occupancy permit provided."

- Closing date passed, no extension was put out there.  

Is the contract active, given the closing date of 7/12/21 has passed?

For context:  The reason closing date had passed was because parties were waiting on the city of St. Louis to inspect and provide occupancy permit.  In order to obtain this permit, repairs needed to be done. Seller had these repairs done, occupancy permit has been obtained, but sicne repairs have been done, seller wants to negoiate price.  

I can provide more details, as needed.  I appreciate any feedback on this.