preclearance refusal

My unmarried partner applied for a defacto to join me in Ireland with our four children wh all live in Nigeria with their mother - two of the kids are Irish citizens. The application was refused based on the reason that I have not continuosly lived in Nigeria with her for two years, the granting of Preclearance may result in a cost to public funds, Insufficient evidence provided of where applicant and sponsor will reside in Ireland. Please is there any other route I could take to address this or any advise at all?