Usually, when the KaiStore isn't visible or it doesn't open or when you don't see some apps or any of announced apps, it’s because there isn’t a valid SIM card inside the phone or the software version of your phone is out of date.
If you do have a SIM card in, there’s a chance it could be inserted incorrectly. To confirm, you can try removing it and adding it back, then attempting the download again.
Also, you should check the software version. Please go to Settings -> Device -> Device Information -> Software. If your KaiOS version is older than 2.5.1 (the software build number may be different), please go to Software Update and update the version up to the most recent one.
In instances when there's no new update for your device, it is worth enabling/disabling Airplane mode in the Settings, and then check for an update.