This is what can happen with live betting. I don't think Stake is at fault or owes you anything. Who knows if you were using a slow VPN or internet connection. Maybe the broadcast you were watching had a delay on it to catch cursing or whatever else... Maybe the odds provider had a couple second delay in processing as a result of any number of things... These companies have hundreds of millions of dollars on the line if things don't work as they should so you know when it comes to live betting they're going to take their time to make sure that all the bets are on the up and up. I'm sorry for your loss here, but if you're live betting one point to the next then you should take a look at being a little too hands on with your bets.
If Stake offering slow service then they have partly at wrong here because they are offering live cashout despite of their system delay that will cause issue like this but since they are protected by their ToS and obviously includes technical error then having an argument about this issue is pointless since the user agree on ToS the moment they sign up the casino.
Some casinos have some rules for the cash-out and at some point, according to their terms and conditions, the casino has the full right to refuse cash-out at what point.
-So at this point, stake.com may have such rules that give them immunity as the casino to refuse the cash out most, especially in this situation we're ops were already running out of time before clicking to cash out.