Flipkart - Flipkart is not providing tax invoice for an item I bought

Flipkart is not providing the full tax invoice for a CMF Phone * Pro I bought on ** June, ****.
I bought the phone for Rs. *****.
When I ordered, it was in exchange of my Poco X* Pro phone. And the amount that I had to pay was Rs. *****. But before delivering the phone, they cancelled the discount and I had to pay Rs. **** to the delivery guy. The tax invoice they are providing is only for Rs. *****. And with that invoice I will not be able to claim the GST for the whole phone. And Flipkart will end up getting away with paying the full GST. Unless they have some other way to fudge the GST amount. Please help me get the whole GST. Summarising my complaint in bite-sized pointers -
*. Flipkart isnt providing tax invoice of an item I bought
*. Flipkart is not showing the total taxable amount they took from me in the invoice they have provided
*. Flipkart cancelled an exchange for unknown reason and because of that I ended up paying more than the actual cost of the product.
Attached - Invoice provided by Flipkart and Proof of Purchase