Zed - let us know how you get on pursuing this issue with the underwriter and, if it comes to it, IFSRA or the FSO. I very much doubt that you will get a refund. Post the relevant portions of the governing terms & conditions if you think there's any point.
You may well be right - I was never arguing that a refund is definitely due. It all boils down to whether under the T&C the company was exposed to a mortality risk.
TBH I don't see how anyone here can opine on the validity of a claim for a refund when they haven't read the T&C. No one (except the OP) knows which company it is with (it could even be a cross border company).
To suggest that there is categorically on chance is (IMO) unhelpful. To suggest that it may be worth following up with an independent resouce will mean the OP has exhausted all reasonable options and should feel more comfortable with the outcome - no matter what it is.