If the local network is up and broadcasting SSIDs (assuming the switch is powering the APs) then it might not be the switch that's the issue. Do you get a valid IP address when you connect directly to the switch or AP? Is there a router you can connect to so you can verify external connectivity?
The Serial number for the switch is located on the underside of the switch on a white label if you'd like to open a ticket. Alternatively, you can get this information from the CLI using the command show version.
Whilst on the CLI, you should verify the images installed on the switch since there are two flash partitions that can hold different firmware. Do this by using the command show flash. You will see a primary and a secondary image as highlighted below:
For Unleashed to see the switch it will need to have SPS (switch image) not SPR (router image). If there is an SPR image in one of the firmware banks you can boot from the other bank:
To boot from primary or secondary.
boot system flash primary
boot system flash secondary
You should then do a write memory
Finally if there is a SPR image in the switch, you can flash it with an SPS image so that in the event of a power outage it will always boot with an SPS image. You can always ensure it's going to boot from one partition by using the command boot system flash primary.