Indigo - Luggage stranded

I flew from Delhi to Berlin on **th August ****. The staff at check in for Indigo conveniently failed to tag my luggage leading it to be left behind at the airport in Delhi. I asked her whether she would be able to resolve it to which she lied stating that it has been managed at the backend. It is now *nd September **** and I am left without my important documents and essential items as an international student in a foreign country. Indigo has been shifting the blame to Turkish as this was a code sharing flight even though Indigo failed to load the luggage itself.

Further, after repeated complaints they generated a tag and said that the luggage has been sent on *st September but it did not reach Berlin again. I demand strict action and a full compensation from Indigo.