It is definitely a SNAD!! Her measurements were off by a few inches in every directions and eBay should recognize that as being significant. If you ordered a pair of shoes and they were a size smaller or larger than the listing it would be a SNAD, same with a pair of jeans or a shirt.
I'd hope the seller would be willing to simply refund the purse, and allow you to ship it back.
I'd hope the seller would be willing to simply refund the purse, and allow you to ship it back.