They did forfeit
So, why did the Sir Ya Khan walk out and blame the umpires for not continuing? It's okay to stand up for one's rights and demand not to be called a cheat without evidence. For that matter, it's also okay to call Darrell Hair a racist cheat (and probably be fined for it). I mean it's definitely okay to protest and lose a test match in a series which you anyway have lost. It's also perhaps okay to protest and therefore ruin the afternoon for many cricket fans.
What is not okay is to say, "....Then we were ready to play but it appears that the umpires are unwilling to go ahead. We find it extraordinary. It is very sad things have come to this..." and then publish such a lame joint statement? Go read the rule book, I say.