Did you win the bet? I have never found a different result with scoreboard, do you have any screenshot? anyway, this is not a DDOS attack.
Most likely he didn't win since he's here complaining about what happened. Wrong scores does happen every now and then i've only experienced it on their NBA live odds and it takes a while to get corrected at the same time it causes their live betting to go down.
Why do I think that after seeing the result in bet365, you will find delay in stake and attempt to place your bet to win the bet, but your intention was not successful!
My guess is that the live scores weren't updating and bet365 is like one of the known sites to quickly update the live scores based on their odds movement. I also use it sometimes but you can't really take advantage of the live scores since stake is quick to follow plus there's a small delay when placing live bets. Back then maybe it was possible I remember someone from their chat said he wagered all the way to platinum through live table tennis since they don't close their lines that fast but now you can't anymore.