Seller not uploading gst invoice on gst portal

If Y is registered under GST then before claiming Input tax credit they must ask the seller to upload invoices which can be viewed in form 2A at Y GST login dashboard. Still Y is eligible to claim Input tax credit on the basis of taxable invoice received from X not matters if X has shown the invoice in GST portal or not. As form GSTR 2 is still deffered hence Y has no option to add an invoice as a counter party. X is eligible for ITC on the basis of taxable invoice.

Also, now whenever a Ewaybill is generated the data is automatically figured out at the dashboard of parties concerned Hence, the sales is monitored and evasion of sales can't be done.

On the other hand, if X is a unregistered dealer and from Seller Y purchase Goods then it's a duty of Y to show such sales in their returns which can't be monitored being just a customer of Y.

Conclusion is Y completely eligible to have input tax credit on the basis of taxable invoice.