If you want the ring at the lowest price, this sounds like the right place ! The only worry might be that they send nothing at all ... which, is OK too, as long as you have a way to dispute the transaction.
Why I give up: the way you have chosen a complex design at an impossible price, does not leave options - it was meant that way. Then, the straight & narrow does not exacty offer the world on a platter ...
Please don't give up. I never even mentioned what my budget was. My ceiling is $7.5 at the high end, but I'd rather it be no more than about $6,200. $4.5k is even better!