ACE Group Sector 150 delays — anyone else facing this?

Sector 150 — honestly, I'm at my wit's end with this project. I'm based in Dubai and invested in a 3BHK at ACE Parkway almost three years back. Builder ne bola tha possession 2.5 saal mein mil jayega, but abhi tak kuch fix nahi hai. They're asking for the next installment for finishing work, but site par progress bohot slow hai yaar. My EMI already started. Can't do a site inspection myself, relying on my brother. Lagta hai they're just delaying to extract more money. Power of attorney se bhi kuch khaas nahi ho raha. Is anyone else facing this with ACE Group in Noida? Kya options hain? Should I contact RERA, ya koi aur way out hai?