Panasonic — ac gas leak

I brought a panasonic 1.5 ton split ac from great eastern, vip road kolkata, westbengal india on 28/3/18. My installation was free but i was charged rs 2500, and my walls were damaged while their poor installation. Within 10 months it stops cooling entirely, service person says gas leak has occurred and charges me rupees 1500 for shifting the outdoor unit, though the initial installation was done by company and my product was within guarantee. While my gas was refilled, leakage was neither detected nor repaired. Within 3-4 days of refill, leakage again starts gas smell coming from outdoor unit, and the tubing is oily, yet their poor technicians cannot fix it. My ac is still within guarantee and i want replacement