Flipkart — Gst law violation

Order I'd:OD[protected]
I have ordered a mobile phone which got delivered to me from banglore. I am currently residing at Ahmedabad. As per gst rules supplier is suppose to mention GSTIN of buyer if available i.e.buyers can have the option to quote their GSTIN so this is an option available to buyer not seller.seller is mandatorily required to quote GSTIN of buyer if he is willing to give GSTIN.but on flipkart many products are sold without having option to quote GSTIN of buyer.this is clearly violation of law and a very high probability of evasion of tax since b2C transactions are not easily traceable.