Sales return in GST

I think now the situation (GST regime) it's not good.
So,
You ll consider your customer and then receive it as GST purchase...

Now u are taking itc of gst on credit note... Then what is need to take itc of vat?? Now u r receiving credit note... On which gst has been charged... Itr ur itc now

This situation is covered by section 142(1) of the transitional provisions. For your customer, its a deemed supply and he need to remove the goods charging GST by raising a tax invoice. You can take the credit on such bill. Alternatively, many are also following the credit note route in this case but that is legally not correct.