received defective voltas ac

I hassan imam purchased voltas split ac Online from snapdeals on 27 march 2016. The product was delivered to me on 2 april 2016 but after instalation the outdoor unit is not functioning.on 8 april i lodge complain to voltas service centre from where i received complain no.16040714747. After two days two guys from service centre visited my home and examined the outdoor and said that the fan blade is defective. Two later they visited again and during repairing broke the blade and gone with asuarance that they will replace it . Now on contacting i get reply that your defective part is order as soon it reach you will get your replacement.till now i am suffering .i have also requested for replace/refund to snapdeals within 7 days but they are also making fool of me by saying get written proof from voltas service that your ac is defective and the service centre is not ready for it.so please advice me of my option.here is product details invoice no sa874f/15-16/17981 item:voltas1.5ton 5star 185eyr/185imr sptit ac. Item code:dh188777. Order no.12533077236