It looks to me like maybe they took the flickr image and cropped out your watermark, the third finger is missing just above where the watermark is.
I think you are in good shape tho since this is placed with Getty, (however that happened you need to find out) and that Homesense is a "real" company with a graphics dept. etc. and they do have to deal with permissions.
There are all sorts of ways they can claim to arrived at the usage of this image, since the watermark was cropped off they could say they got it from some other random website or even maybe getty themselves subbed it out to another royalty free subcontractor stock group or disc- maybe that is why they don't know exactly. But the fact that it is not the whole image suggests something less "legal."
I think its getty's mess to clean up but you should get all the details from Homesense or your Getty agent should, like number of copies and distribution area, ie, canada, n. america, worldwide, etc. and duration.
Then you and they can come up with an appropriate price.
Don't be surprised if the usage they come up with is low- not to be negative but the image is not unique, they probably can get similar in royalty free for very low amounts even considering the probable high number of copies.
This is the reality of stock today- shockingly low rates.