there was no One Plus with them. People who booked One Plus, their orders are cancelled without consent and it's removed from their carts. Their Facebook page is full with such complaints
I found on oneplus india forums, people wrote around 100 pcs were only with flipkart. That's their limited stocks! Someone from the forum managed to book it, he claims to have 100 Mbps internet plab so it loaded within a flash and he booked.