Conversation so far:
What happened with the deposition?
Lumumba denounced his dismissal over the radio as illegitimate, and in turn labeled Kasa-Vubu a traitor and declared him deposed.
Did Kasa-Vubu depose him?
Still, Parliament did not back Lumumba's dismissal of Kasa-Vubu, creating a constitutional crisis.
How did they solve this problem?
On 13 September, the Parliament held a joint session between the Senate and the Assembly.
Though several members short of a quorum, they voted to grant Lumumba emergency powers.
What happened after this?
On 14 September, a coup d'etat organised by Colonel Mobutu politically incapacitated both Lumumba and Kasa-Vubu.

Question: What did Lumumba do about this?
Self-contained rewrite: What did Lumumba do about the coup d'etat by Colonen Mobutu?