A quick google would suggest that ring is far too large and wide for the size of the hole, most I can see are thinner.
With the large gaps as well, unless you are happy with the weight of the hammer and fancy trying to re-handle it yourself, I'd say send it back but request the seller inspects it first so you don't get a repeat.
If they send another and it's also crap - you can either send it back again (more of YOUR time wasted), or just keep it - and do a chargeback and contact the seller saying you are doing a chargeback because they sent another faulty one despite asking for a quality check, and you are having it repaired at your expense, hence the chargeback.
Then rehandle it yourself - it's actually not that hard, just take your time with the head end to get the best fit you can then buy a FLAT hammer wedge - about £2. You could do a bi-axis wedge, WOODEN for the first, and metal for the second, which is a bit more forgiving and makes the shaping a little easier for the head as you are splaying the wood in two axis.
Don't forget to drill relief holes at the base where you've cut the splits. 2mm is enough to stop the split from travelling, these should not be visible under the head.
LOL or just go buy a fancy hammer
just in case:
https://www.popularwoodworking.com/tool ... le-part-1/
I followed this one:
http://www.robin-wood.co.uk/wood-craft- ... xe-handle/