Celia is available to customers in Nigeria. The cash and utility features are, in the app's own words, open to the Nigerian audience, and access is tied to being in the country.
If you open Celia from outside Nigeria, access is restricted. Your balances may look empty and your tokens may appear to be missing. This is only a location restriction: nothing has been lost, and your account is intact.
Because your crypto is self-custodial, you can always reach it with your recovery phrase even while the app is restricted for you. If you are travelling and need to see or move your crypto, read "My tokens are missing or my balance looks empty," which explains how to do that safely.