Betfred made a counter claim that the player broke the rules in ways that they will not discuss on the forum. What has happened is that the PAB process has begun. There is still some way to go before a conclusion is reached. Betfred have somewhat dug a hole for themselves by indulging in the chicanery of removing the Pontoon game and pretending it never happened, rather than coming straight out with a clear statement that rules were broken that voided the play, and as a consequence, the prize. If it is not about the game the OP played, why remove it as part of the initial response to this issue, and then compound matters by banning the whole country of Canada just because ONE player there tried to con their way to a near £30K prize. The whole thing makes it look like Betfred are unsure of their position, and maybe even unsure that any rules were broken. Instead, they are reacting as though there is a technical issue with the game itself, and that it dealt a hand it was not meant to, or that the hand was the result of a malfunction.
Whilst the odds are 1 in 80,000, this does not mean that an individual player would have to play 80000 hands in order to hit, and it could be that by pure chance a whole bunch of players hit the prize winning hand long before the expected number of hands have been played. It is also possible that a player might play 800,000 hands and still not hit it. If a player complained the promotion was rigged just because he couldn't win a Jag after 10x the expected number of hands he would be told this is entirely possible, and not evidence of any malpractice.
It still looks to me like Betfred have belatedly realised that the odds are against them, and that they stand to give out a whole showroom of Jags, rather than the one or two they had budgeted for. They are dealing with this by continually tweaking the terms to pull the odds back in their favour, but do not want to lose face by ending the promo early, even though this is provided for in the terms.