Delta Flight and upgrade questions

Hi,

thanks in advance for any advice on this -

I have a Delta flight booked from Edinburgh to New York and return in October this year.
I booked through a third party and have been on the Delta website and the itinerary is there.

Two questions -
1 - When I was on the Delta website, I seemed to have secured free seats in 'comfort+' cabin. Is this common or will I soon get some kind of invoice (nothing showed up on screen as I made the seat selection and it did appear to show 'Free')

2 - I have a batch of Virgin airmiles (around 57,000). I wondered if it is possible to upgrade the Delta flight to business class using airmiles (even one-way)? If so, do I just call flying club or Delta?

On 2 you can't use VS miles to upgrade a DL operated flight.

In any case it is unlikely that a ticket booked via a 3rd party would be in an upgradable bucket.