EU Login provides you with a digital identity per account. If you logged in only using your eID first, it automatically created an account. If you create another account and link your eID to it, the first identity that was automatically generated by the system is erased and any data that other applications may have stored for this identity is unfortunately lost.
Please contact the support team from the application that you worked with to try to recover your data in case you lost it due to this manipulation. Maybe the support team of that application can recover the data linked to the account that was erased.