IKEA Delivered My HEMNES Sofa Without Package No 1 so We Can’t Assemble It

I bought a HEMNES sofa with order number 212306241735876 through the IKEA Turkey online store. The product was delivered to us in 3 pieces (packages numbered 3 and 4 were taped together) by ARVATO Logistics. We received packages numbered 2, 3, and 4, but package No. 1 never arrived. How do I know that packages 3 and 4 were combined and counted as one? There has been no response from the logistics company, and IKEA claims that all packages were shipped, yet we still do not have package No. 1. We are unable to assemble the product. It’s disappointing to see a brand we’ve trusted for its corporate image fall into such a situation. I’ve seen many similar complaints on this site. My request is simple: I want package No. 1 to be sent to me. If it is not, I would like to inform you that I will pursue legal action.