Export of Services under GST - Goods and Services Tax - GST

Seeking experts guidance in the forum In one of our case, client have received substantial amount in bank account towards ecommerce website and development services provided to clients located outside India during FY 2024-25. Client is registered taxpayer in GST and have filed nil return till Feb-25. Payment has directly been received in INR in his bank account. Billing is done in USD to clients. What happen is that client have not filed any LUT for FY 2024-25 for availment of benefit of export of services without payment of tax as he is not aware for any of such compliance. My question is that what treatment should be done in respect of payment received during the year FY 2024-25 (till March-25) and should we pay GST on such export considering the same as export made with payment of tax @ 18% on total payment received during the year and its treatment in March-25 GSTR-1 GSTR-3B ?