Please advise if we didn’t get permission to go to ground floor for Sae’i then Is it allowed to perform Sae’i on first floor if authorities didn’t allow us to perform Sae’i on ground floor and is our umrah valid in these circumstances.

Unfortunately, no.
You are still in Ihram status. Hence you all need to wear ihram and go to Makkah to perform saei and rest of parts.
If you are not allowed or able to do so, then each one of you need to sacrifice a goat and then make taqseer.